Technical Manual - Master Lock

Commercial Products
T E C H N I C A L
M A N U A L
ISSUE 07.10

Table of Contents
Index by Model No. 1
ProSeries ® 6270 & 6271 Lock Service Procedure 2
ProSeries ® Rekeyables Service Procedure 3
ProSeries ® 6230 Locks Service Procedure 5
ProSeries ® Rekeyables Component Parts 4,6
ProSeries ® Interchangeable Core Service Procedure 7
ProSeries ® Interchangeable Core Component Parts 8
ProSeries ® Door Hardware Service Procedure 9
ProSeries ® Door Hardware Component Parts 10
21, 24, 25, 27 and 101 Laminated Rekeyables Service Procedure 11
Python Cylinder Compatible Products Service Procedure 11
Cylinders and Retainers 13-17
Cylinder Service Procedure 18
Keying 19-22
Improved 6000 and 7000 Keyways 23
Keys and Keyways 24
Bitting Specifications 25
ProSeries ® Actuators, Retainers and Drivers 26-27
Tools 28
Lock Lubricants 29
Terminology 30-38
Service
Product No. Procedure Parts
6121 3 4
6125 3 4
6127 3 4
6230 5 6
6270 2 2
6271 2 2
6321 3 4
6325 3 4
6327 3 4
6421 7 8
Model Number Index Service Procedures and Parts
Service
Product No. Procedure Parts
6427 7 8
6521 7 8
6527 7 8
6621 9 10
6627 9 10
6721 9 10
6727 9 10
6830 3 4
6831 7 8
6835 3 6
1
Service
Product No. Procedure Parts
6836 7 8
6840 3 4
6841 7 8
6842 9 10
6850 3 6
6851 7 8
6852 9 10
7030 3 6
7031 7 8
7035 3 6
Service
Product No. Procedure Parts
7036 7 8
7040 3 6
7041 7 8
7042 9 10
7045 3 6
7046 7 8
7047 9 10
7050 3 6
7051 7 8
7052 9 10

Master Lock introduced the ProSeries ® product line in 1992 with Weather Tough ® and High Security, iron
shrouded, rekeyable padlocks. Intent on providing locksmiths with greater ease and flexibility, Master Lock
designed the padlocks to use standard components across the line. Since then, ProSeries ® has grown to
include solid body padlocks in Brass, Steel and Aluminum to further satisfy corrosion, security and safety
requirements. Master Lock has also added extensive interchangeable core and door hardware cylinder
options to create maximum options for padlock integration into facility padlock and door lock systems.
Today, ProSeries ® is the only product line available for so many different applications, making Master
Lock the source for complete commercial security.
ProSeries® 6270 & 6271 Locks Service Procedure
The 6270 is a solid steel body lock. The 6271 is a zinc die cast body lock.
Disassembling for servicing these two locks may be accomplished by
following the steps listed below (refer to the diagram at the right for parts
and orientation).
• Loosen or remove the cylinder mounting screw, H, on the back of the
lock body with a 3/32" hex wrench. (Early production used 2.5mm)
• Use the key to unlock the shackle. (If key is unavailable you will have to
use another method to unlock the shackle).
• Pull on the cylinder to remove it.
• For rekeying, loosen set screw, J, (1.5 mm), inside the last pin chamber
to allow 180° rotation of the plug.
• Align pin chambers in plug with service holes in the bottom of the shell
to remove existing bottom pins and replace with new combination.
• Rotate plug to key pull position and tighten the set screw in the last pin
chamber.
The order may be reversed to reassemble the lock.
These locks are available with the K6000 and K7000 key. They are also
available with the EDGE System keyways WP4 and WP6. By specifying
the 600A and 700A keyways they can also be supplied as compatible with
American Lock products in the field.
Identification
Code Description Part Number
Stock Master 6 pin cylinder. Includes zero
bitted cylinder with shackle and two key blanks.
297W7000KZ
Optional Master 5 pin cylinder. Includes zero
bitted cylinder with shackle and two key blanks.
297W6000KZ
A & C Optional American 6 pin W700A cylinder.
Includes zero bitted cylinder with shackle
and two key blanks.
Optional American 5 pin W600A cylinder.
297W700AKZ
Includes zero bitted cylinder with shackle
and two key blanks.
297W600AKZ
Optional EDGE System 6 pin cylinder. Includes
zero bitted cylinder with shackle but no blanks
297WP6UN
Optional EDGE System 4 pin cylinder. Includes
zero bitted cylinder with shackle but no blanks
297WP4UN
H Hex Screw (uses 3/32" hex wrench)
6270-0400
(Contains 6 screws)
J Hex Screw (uses 1.5mm hex wrench)
6270-0401
(Contains 6 screws)
These locks are NRK (Non Removable Key) function. Key can only be
removed if shackle is locked. Because of the lock design, the shackle may
be locked open or locked closed via this function.
2
J
H
C
A

ProSeries® Rekeyables Service Procedure
6121, 6125, 6127, 6321, 6325, 6327, 6830, 6835, 6840, 6850, 7030,
7035, 7040, 7045, 7050 Series
All of the ProSeries ® locks have a generic construction technology that
allows for a uniform assembly and disassembly technique. Below is a stepby-step
procedure for disassembling one of these padlocks (refer to
diagram at right for parts and orientation). The only exceptions to this
procedure will be the Door Hardware and IC versions of the lock.
• Use the key to unlock the shackle, A. (If the key is unavailable you will
have to use another method to unlock the shackle).
• Use a 7/64" hexagonal wrench to remove the mounting screw located
inside the toe side shackle hole.
• Holding the trap door, D, in place, lock the shackle, A, into the padlock
body. (This relieves pressure on the actuator, E).
• Remove the trap door, D, and the nut, F.
• Remove the cylinder, C.
• Remove the actuator, E.
• Remove the locking ball bearings, B, and shackle, A.
The order may be reversed to reassemble the lock. A light application of
assembly grease may be used to hold the ball bearings in place during
assembly.
If the lock only needs to be rekeyed, it is not necessary to remove the
actuator, ball bearings, or shackle.
Two functions are available in the locks, NKR (Non Key Retaining) and
NRK (Non Removable Key) and both functions are accomplished as a
design feature of the actuator.
The NKR, non key retaining, function actuator used in the lock has a
projection on one side. You should note the orientation of this projection
when removing the actuator so that you can easily reinstall it during the
reassembly process. Actuators are supplied with different sizes and two
different styles have been used in the ProSeries ® locks. Consult the
Actuator section, page 26, of this manual for more detailed information.
The NRK, non removable key, function actuator does not have a
projection to help with orientation and you will have to rely on the
position of the half-moon shaped actuator the tail of the cylinder contacts.
Again, different sizes and styles are available for use in the ProSeries ®
locks, so consult the Actuator section, page 26, of this manual for more
detailed information.
See component parts list on page 4 and 6.
3
E
F
C
D
B
G
A

ProSeries® Rekeyables Component Parts
Weather Tough ®
Iron Shroud
Solid Brass
a c
b
a c
a c
d d
d
b
b
Weather Tough Shrouded Brass/Aluminum/Steel Round Steel Shrouded Solid Steel
Vertical
Components
Model # Shackle Shackle Ball Bearings Cylinder Trap Door Actuator Flared Nut Screw
Clearance (b) NKR* NRK**
A B C D E F G
2-1/8" Wide Laminated Steel Body. Shackle Dimensions: a: 5/16" c: 7/8"
6121 1-1/8" 293S6121
6121LF
6121LJ
1-1/2"
2-3/8"
293LF6121
293LJS6121
6121-0427
See List
Page 18
6121-0420 6121-0423 6121-0424 6121-0421 6121-0422
6121LN 5-3/4" 293LNS6121
2-3/8" Wide Laminated Steel Body. Shackle Dimensions: a: 3/8" c: 7/8"
6125
6125LJ
1-3/8"
2-3/8"
293S6125
293LJS6125
6121-0427 See List, P. 18 6121-0420 6121-0423 6121-0424 6121-0421 6121-0422
2-5/8" Wide Laminated Steel Body. Shackle Dimensions: a: 7/16" c: 7/8"
6127 1-3/8" 293S6127
6127LH
6127LJ
1-7/8"
2-3/8"
293LHS6127
293LJS6127
6121-0427
See List
Page 18
6121-0420 6121-0423 6121-0424 6121-0421 6121-0422
2-1/8" Wide Laminated Steel Body. Shackle Dimensions: a: 5/16" c: 7/8"
6321 3/4" 293S6321 6121-0427 See List, P. 18 6121-0420 6121-0423 6121-0424 6121-0421 6121-0422
2-3/8" Wide Laminated Steel Body. Shackle Dimensions: a: 3/8" c: 7/8"
6325 3/4" 293S6325 6121-0427 See List, P. 18 6121-0420 6121-0423 6121-0424 6121-0421 6121-0422
2-5/8" Wide Laminated Steel Body. Shackle Dimensions: a: 7/16" c: 7/8"
6327 3/4" 293S6327 6121-0427 See List, P. 18 6121-0420 6121-0423 6121-0424 6121-0421 6121-0422
1-9/16" Wide Solid Brass Body. Shackle Dimensions: a: 1/4" c: 25/32"
6830 1-1/16" 293S6830
6830B
6830LF
1-1/16"
1-9/16"
293B6830
293LFS6830
0220-0302
See List
Page 18
6830-0420 6831-0421 6831-0422 6121-0421 6121-0422
6830LT 3" 293LTS6830
1-3/4" Wide Solid Brass Body. Shackle Dimensions: a: 5/16" c: 29/32"
6840 1-3/16" 293S6121
6840B 1-3/16" 293B6840
6840LF
6840LJ
1-9/16"
2-7/16"
293LFS6121
293LJS6121
6121-0427
See List
Page 18
6121-0420 6841-0421 6121-0424 6121-0421 6121-0422
6840BLJ 2-7/16" 293LJB6840
6840LN 5-3/4" 293LNS6121
* NKR Non Key Retaining. Key can be removed anytime.
**NRK Non Removable Key. Key can only be removed if shackle is in locked position.
4

ProSeries® 6230 Locks Service Procedure
The 6230 is a solid steel body lock using the ProSeries ® standard ball
bearing locking mechanism. Disassembling for servicing is similar to the
rekeyables and may be accomplished by following the steps listed below
(refer to diagram at right for parts and orientation).
• Use the key to unlock the shackle, A. (If the key is unavailable you will
have to use another method to unlock the shackle).
• Use a 7/64" hexagonal wrench to remove the mounting screw located
inside the toe side shackle hole.
• Holding the trap door, D, in place, lock the shackle, A, into the padlock
body. (This relieves pressure on the actuator.)
• Remove the trap door, D, and the nut, F.
• Remove the cylinder, C.
• Remove the actuator, E.
• Remove the locking ball bearings, B, and shackle, A.
The order may be reversed to reassemble the lock. A light application of
assembly grease may be used to hold the ball bearings in place during
assembly.
If the lock only needs to be rekeyed, it is not necessary to remove the
actuator, ball bearings, or shackle.
Two functions are available in the locks, NKR (Non Key Retaining) and
NRK (Non Removable Key) and both functions are accomplished as a
design feature of the actuator.
The NKR, non key retaining, function actuator used in the lock has a
projection on one side. You should note the orientation of this projection
when removing the actuator so that you can easily reinstall it during the
reassembly process.
The NRK, non removable key, function actuator does not have a
projection to help with orientation and you will have to rely on the
position of the half-moon shaped actuator that the tail of the cylinder
contacts.
See component parts list on page 6.
5
E
F
C
D
B
G
A

ProSeries® Rekeyables Component Parts
Solid Brass
Solid Aluminum
Solid Steel
Shrouded
Solid Steel
a c
b
a c
a c
d d
d
b
b
a c
b b
Vertical
Components
Model # Shackle Shackle Ball Bearings Cylinder Trap Door Actuator Flared Nut Screw
Clearance (b) NKR* NRK**
A B C D E F G
2" Wide Solid Brass Body. Shackle Dimensions: a: 3/8" c: 29/32"
6850 1-1/2" 293S6125
6850B
6850LJ
1-1/2"
2-1/2"
293B6850
293LJS6125
6121-0427
See List
Page 18
6121-0420 6841-0421 6121-0424 6121-0421 6121-0422
6850BLJ 2-1/2" 293LJB6850
1-9/16" Wide High Visibility Aluminum Body. Shackle Dimensions: a: 1/4" c: 25/32"
6835RED 1-1/16" 293S6830
6835LFRED 1-9/16" 293LF6830
6835ORJ 1-1/16" 293S6830
6835LFORJ 1-9/16" 293LFS6830
6835YLW 1-1/16" 293S6830
6835LFYLW
6835GRN
1-9/16"
1-1/16"
293LFS6830
293S6830
0220-0302
See List
Page 18
6830-0420 6831-0421 6830-0422 6121-0421 6121-0422
6835LFGRN 1-9/16" 293LFS6830
6835BLU 1-1/16" 293S6830
6835LFBLU 1-9/16" 293LFS6830
6835BLK 1-1/16" 293S6830
6835LFBLK 1-9/16" 293LFS6830
1-9/16" Wide Solid Steel Body. Shackle Dimensions: a: 1/4" c: 25/32"
7030
7030LF
7030LT
1-1/16"
1-9/16"
3"
293S6830
293LFS6830
293LTS6830
0220-0302
See List
Page 18
6830-0420 6831-0421 6830-0422 6121-0421 6121-0422
1-3/4" Wide Solid Steel Body. Shackle Dimensions: a: 5/16" c: 29/32"
7040 1-3/16" 293S6121
7040LF
7040LJ
1-9/16"
2-1/2"
293LF6121
293LJS6121
6121-0427
See List
Page 18
6121-0420 6841-0421 6121-0424 6121-0421 6121-0422
7040LN 5-5/8" 293LN6121
2" Wide Solid Steel Body. Shackle Dimensions: a: 3/8 c: 29/32"
7050
7050LJ
1-1/2"
2-1/2"
293S6125
293LJS6125
6121-0427
See List
Page 18
6121-0420 6841-0421 6121-0424 6121-0421 6121-0422
2-1/2" Wide Round Solid Steel Body. Shackle Dimensions: A: 7/16" C: 7/8"
6230
6230LH
1-1/8"
2
293S6230
293LHS6230
6121-0427
See List
Page 18
6121-0420 6121-0425 6121-0426 6121-0421 6121-0422
1-9/16" Wide Solid Steel Body. Shackle Dimensions: a: 1/4" c: 25/32"
7035 1-1/16" 293S6830 See List, P. 18 6830-0420 6831-0421 6830-0422 6121-0421 6121-0422
1-3/4" Wide Solid Steel Body. Shackle Dimensions: a: 5/16" c: 29/32"
7045 1-3/16" 293S6121 Page 18 6121-0420 6841-0421 6121-0424 6121-0421 6121-0422
Note: the 296W6000 cylinder is pinned with only 5 pins, for 6 pins order 296W7000
* NKR Non Key Retaining. Key can be removed anytime.
**NRK Non Removable Key. Key can only be removed if shackle is in locked position.
6
a c
d d
Weather Tough Shrouded Brass/Aluminum/Steel Round Steel Shrouded Solid Steel

ProSeries® Interchangeable Core Service Procedure
6421, 6427, 6521, 6527, 6831, 6836, 6841, 6851, 7031, 7036, 7041,
7046, 7051 Series
The ProSeries ® Interchangeable Core locks employ a construction
technology similar to that used in the Rekeyables. It also allows for a
uniform assembly and disassembly technique. Below is the step by step
procedure for disassembling this version of padlock (refer to diagram at
right for parts and orientation). The only exceptions to this procedure
will be the Rekeyables and Door Hardware versions of the lock.
• Use the control key to remove the IC cylinder, C. (If key is unavailable
you will have to use another method).
• Remove the ring retainer.
• Remove the steel retainer plate.
• Remove the throw member.
• Remove the actuator, E.
• Remove the locking ball bearings, B, and shackle, A.
The order may be reversed to reassemble the lock. A light application of
assembly grease may be used to hold the ball bearings in place during
assembly.
If the lock only needs to be rekeyed, it is not necessary to remove the ring
retainer, retainer plate, actuator, ball bearings, or shackle.
Two functions are available in the locks, NKR (Non Key Retaining) and
NRK (Non Removable Key) and both functions are accomplished as a
design feature of the actuator.
The NKR, non key retaining, function actuator used in the lock has a
projection on one side. You should note the orientation of this projection
when removing the actuator so that you can easily reinstall it during the
reassembly process. Actuators are supplied with different sizes and
orientations, and two different styles have been used in the ProSeries ®
locks. Consult the Actuator section, page 26, of this manual for more
detailed information.
The NRK, non removable key, function actuator does not have a
projection to help with orientation and you will have to rely on the
position of the half-moon shaped actuator the tail of the cylinder contacts.
Again, different sizes and styles are available for use in the ProSeries ®
locks, so consult the Actuator section, page 26, of this manual for more
detailed information.
See component parts list on page 8.
7
E
B
6421-0451
6421-0452
6421-0453
C
A

ProSeries® Interchangeable Core Component Parts
Weather Tough ®
Iron
Shroud
Solid Brass
Solid Aluminum
Solid Steel
Shrouded
Solid Steel
a c
b
d
Shrouded
a c
b
d
a c
a c
b b
d d
Brass/Aluminum/Steel Round Steel Shrouded Solid Steel
Vertical
Components
Model # Shackle Shackle Ball Bearings Cylinder Trap Door Actuator Flared Nut Screw
Clearance (b) NKR* NRK**
A B C D E F G
2-1/8" Wide Laminated Steel Body. Shackle Dimensions: a: 5/16" c: 7/8"
6421 1-1/8" 293S6121
6421LF
6421LJ
1-1/2"
2-3/8"
293LF6121
293LJS6121
6121-0427 See List P.14 N/A 6121-0423 6121-0424 N/A N/A
6421LN 5-3/4" 293LN6121
2-5/8" Wide Laminated Steel Body. Shackle Dimensions: a: 7/16" c: 7/8"
6427 1-3/8" 293S6127
6427LH
6427LJ
1-7/8"
2-3/8"
293LHS6127
293LJ6127
6121-0427 See List P.14 N/A 6121-0423 6121-0424 N/A N/A
6427LN 5-3/4" 293LN6127
2-1/8" Wide Laminated Steel Body. Shackle Dimensions: a: 5/16" c: 7/8"
6521 3/4" 293S6321 6121-0427 See List P.14 N/A 6121-0423 6121-0424 N/A N/A
2-5/8" Wide Laminated Steel Body. Shackle Dimensions: a: 7/16" c: 7/8"
6527 3/4" 293S6327 6121-0427 See List P.14 N/A 6121-0423 6121-0424 N/A N/A
1-9/16" Wide Solid Brass Body. Shackle Dimensions: a: 1/4" c: 25/32"
6831 1-1/16" 293S6830
6831B
6831LF
1-1/16"
1-9/16"
293B6830
293LFS6830
0220-0302 See List P.14 N/A 6831-0421 6830-0422 N/A N/A
6831BLF 1-9/16" 293LFB6830
1-3/4" Wide Solid Brass Body. Shackle Dimensions: a: 5/16" c: 29/32"
6841 1-3/16" 293S6121
6841B 1-3/16" 293B6840
6841LF 1-1/2" 293LFS6121 6121-0427 See List P.14 N/A 6841-0421 6121-0424 N/A N/A
6841LJ 2-7/16" 293LJS6121
6841BLJ 2-7/16" 293LJB6840
2" Wide Solid Brass Body. Shackle Dimensions: a: 3/8" c: 29/32"
6851 1-1/2" 293S6125
6851B
6851LJ
1-1/2"
2-1/2"
293B6850
293LJ6125
6121-0427 See List P.14 N/A 6841-0421 6121-0424 N/A N/A
6851BLJ 2-1/2" 293LJB6850
1-9/16" Wide High Visibility Aluminum Body. Shackle Dimensions: a: 1/4" c: 25/32"
6836RED 1-1/16" 293S6830
6836LFRED 1-9/16" 293LFS6830
6836LTRED 3" 293LTS6830
6836ORJ 1-1/16" 293S6830
6836LFORJ 1-9/16" 293LFS6830
6836LTORJ 3" 293LTS6830
6836YLW 1-1/16" 293S6830
6836LFYLW 1-9/16" 293LFS6830
6836LTYLW
6836GRN
3"
1-1/16"
293LTS6830
293S6830
0220-0302 See List P.14 N/A 6831-0421 6830-0422 N/A N/A
6836LFGRN 1-9/16" 293LFS6830
6836LTGRN 3" 293LTS6830
6836BLU 1-1/16" 293S6830
6836LFBLU 1-9/16" 293LFS6830
6836LTBLU 3" 293LTS6830
6836BLK 1-1/16" 293S6830
6836LFBLK 1-9/16" 293LFS6830
6836LTBLK 3" 293LTS6830
1-9/16" Wide Solid Steel Body. Shackle Dimensions: a: 1/4" c: 25/32"
7031 1-1/16" 293S6830
7031LF 1-9/16" 293LFS6830 0220-0302 See List P.14 N/A 6831-0421 6830-0422 N/A N/A
7031LT 3" 293LTS6830
1-3/4" Wide Solid Steel Body. Shackle Dimensions: a: 5/16" c: 29/32"
7041
7041LJ
1-3/16"
2-1/2"
293S6121
293LJS6121
6121-0427 See List P.14 N/A 6841-0421 6121-0424 N/A N/A
2" Wide Solid Steel Body. Shackle Dimensions: a: 3/8" c: 29/32"
7051
7051LJ
1-1/2"
2-1/2"
293S6125
293LJS6125
6121-0427 See List P.14 N/A 6841-0421 6121-0424 N/A N/A
1-9/16" Wide Solid Steel Body. Shackle Dimensions: a: 1/4" c: 25/32"
7036 1-1/16" 293S6830 0220-0302 See List P. 14 N/A 6831-0421 6830-0422 N/A N/A
1-3/4" Wide Solid Steel Body. Shackle Dimensions: a: 5/16" c: 29/32"
7046 1-3/16" 293S6121 6121-0427 See List P. 14 N/A 6841-0421 6121-0424 N/A N/A
* NKR Non Key Retaining. Key can be removed anytime. **NRK Non Removable Key. Key can only
be removed if shackle is in locked position.
8

ProSeries® Door Hardware Service Procedure
6621, 6627, 6721, 6727, 6842, 6852, 7042, 7047, 7052 Series
The ProSeries ® Door Hardware locks employ a construction technology
similar to that used in the Rekeyables. It also allows for a uniform
assembly and disassembly technique. Below is the step by step procedure
for disassembling this version of padlock. The only exception to this
procedure will be the IC version of the lock.
• Use the key to unlock the shackle, A. (If key is unavailable you will have
to use another method to unlock the shackle).
• Use a 7/64" hexagonal wrench to remove the mounting screw located
inside the toe side shackle hole.
• Holding the plug retainer, D, in place, lock the shackle, A, into the
padlock body. (This relieves pressure on the actuator.)
• Remove the cylinder driver, K, with the cylinder, C.
• Remove the driver if it did not come out with the cylinder adapter and
the cylinder.
• Remove the actuator, E.
• Remove the locking ball bearings, B, and shackle, A.
The order may be reversed to reassemble the lock. A light application of
assembly grease may be used to hold the ball bearings in place during
assembly.
If the lock only needs to be rekeyed, it is not necessary to remove the
actuator, ball bearings, or shackle.
Two functions are available in the locks, NKR (Non Key Retaining) and
NRK (Non Removable Key) and both functions are accomplished as a
design feature of the actuator.
The NKR, non key retaining, function actuator used in the lock has a
projection on one side. You should note the orientation of this projection
when removing the actuator so that you can easily reinstall it during the
reassembly process. Actuators are supplied with different sizes and two
different styles have been used in the ProSeries ® locks. Consult the
Actuator section, page 26, of this manual for more detailed information.
The NRK non removable key, function actuator does not have a
projection to help with orientation and you will have to rely on the
position of the half-moon shaped actuator the tail of the cylinder contacts.
Again, different sizes and styles are available for use in the ProSeries ®
locks, so consult the Actuator section, page 26, of this manual for more
detailed information.
See component parts list on page 10.
Door Hardware Cylinder Drivers (K), page 26, 27.
Lori 298-0626
Medeco 298-0627
Schlage 298-0628
Lockwood (Australia) 298-0625
9
C
K
E
B
D
G
A

ProSeries® Door Hardware Component Parts
Weather Tough ®
Iron
Shroud
Solid Brass
Solid Steel
Shrouded
Solid Steel
a c
b
a c
b
a c
d d
d
d
Weather Tough Shrouded Brass/Aluminum/Steel Shrouded Round Solid Steel Steel Shrouded Solid Steel
Vertical
Components
Model # Shackle Shackle Ball Bearings Cylinder Retainer Actuator Flared Nut Screw
Clearance (b) NKR* NRK**
A B C D E F G
2-1/8" Wide Laminated Steel Body. Shackle Dimensions: a: 5/16" c: 7/8"
6621 1-1/8" 293S6121
6621LF
6621LJ
1-1/2"
2-3/8"
293LF6121
293LJS6121
6121-0427 See List P.15 298-0629 6121-0423 6121-0424 N/A 6621-0450
6621LN 5-3/4" 293LN6121
2-5/8" Wide Laminated Steel Body. Shackle Dimensions: a: 7/16" c: 7/8"
6627 1-3/8" 293S6127
6627LH 1-7/8" 293LHS6127
6121-0427 See List P.15 298-0629 6121-0423 6121-0424 N/A 6621-0450
6627LJ 2-3/8" 293LJ6127
b
a c
b
6627LN 5-3/4" 293LN6127
2-1/8" Wide Laminated Steel Body. Shackle Dimensions: a: 5/16" c: 7/8"
6721 3/4" 293S6321 6121-0427 See List P.15 298-0629 6121-0423 6121-0424 N/A 6621-0450
2-5/8" Wide Laminated Steel Body. Shackle Dimensions: a: 7/16" c: 7/8"
6727 3/4" 293S6327 6121-0427 See List P.15 298-0629 6121-0423 6121-0424 N/A 6621-0450
1-3/4" Wide Solid Brass Body. Shackle Dimensions: a: 5/16" c: 29/32"
6842 1-3/16" 293S6121
6842B 1-3/16" 293B6840
6842LF 1-1/2" 293LFS6121 6121-0427 See List P.15 298-0629 6841-0421 6121-0424 N/A 6621-0450
6842LJ 2-1/2" 293LJS6121
6842BLJ 2-1/2" 293LJB6840
2" Wide Solid Brass Body. Shackle Dimensions: a: 3/8" c: 29/32"
6852 1-1/2" 293S6125
6852B
6852LJ
1-1/2"
2-1/2"
293B6850
293LJS6125
6121-0427 See List P.15 298-0629 6841-0421 6121-0424 N/A 6621-0450
6852BLJ 2-1/2" 293LJB6850
1-3/4" Wide Solid Steel Body. Shackle Dimensions: a: 5/16" c: 29/32"
7042
7042LJ
1-3/16"
2-1/2"
293S6121
293LJS6121
6121-0427 See List P.15 298-0629 † 6121-0423 6121-0424 N/A 6621-0450
2" Wide Solid Steel Body. Shackle Dimensions: a: 3/8" c: 29/32"
7052
7052LJ
1-1/2"
2-1/2"
293S6125
293LJ6125
6121-0427 See List P.15 298-0629 † 6121-0423 6121-0424 N/A 6621-0450
1-3/4" Wide Solid Steel Body. Shackle Dimensions: a: 5/16" c: 29/32"
7047 1-3/16" 293S6121 6121-0427 See List. P.15 298-0629 † 6121-0423 6121-0424 N/A 6621-0450
* NKR Non Key Retaining. Key can be removed anytime.
**NRK Non Removable Key. Key can only be removed if shackle is in locked position.
10
† Check milling in lock to use 6121-0423.

Laminated Rekeyable Service Procedure
Padlock model numbers 21, 24, 25, 27 and 101 are laminated steel padlocks that have a trap door you can remove so that the
cylinder may be exchanged or rekeyed. The model 24 has a laminated brass plate body.
Cylinder Replacement Instructions
• Unlock padlock. Withdraw key.
Turn shackle away from opening.
• Insert hex wrench into shackle opening to engage socket screw.
• Lift out retainer plate. Tip padlock to slide cylinder out.
To install new cylinder, insert protruding end first. Re-assemble
by reversing above three steps.
NOTE: When using “WO” versions of the No. 21, 24, 25, 27 or
101 padlock, use a screwdriver initially to open shackle. Insert tip
through opening in bottom plate. Turn mechanism as shown to
trip shackle release.
All laminated padlock bodies may be ordered without shackles installed to allow you to stock the
different length shackles and thereby reduce your inventory investment. Once a shackle has been
installed and the kick plate hammered in place the shackle cannot be changed.
Python Compatible Products Service Procedure
REKEYABLE COUPLER LOCKS 34, 35, 37 & 39
The new rekeyable versions of the coupler locks may be identified
by their dark gray or black color and have in them a Python
cylinder that can be rekeyed using the 8491 keying kit following
the instructions on page 21 of this manual. As with all Python
cylinder products, use the removal tool when in the unlocked
position to pull the plug from the lock body. If you don’t have the
removal tool, a hook pick can be used to retract the retainer
tumbler at the back of the keyway.
379ATPY UNIVERSAL COUPLER LOCK
Two versions of the number 379 lock are available. Only the commercial version is rekeyable.
The retail version is part number 379DAT, has a chrome finish and is not rekeyable. The
commercial version has the same dark gray or black finish as the 34, 35, 37 & 39 models above
and has the part number 379ATPY.
The cylinder plug in the 379ATPY uses the Python
cylinder mechanism but the plug cannot be interchanged with other Python
cylinders. As shown here, it has a rod like projection from the rear of the plug. Spare
plugs may be ordered using part number 8401-0340.
11
CYLINDER
RETAINER
RETAINER
SCREW
®
REAR
FRONT
PLUG
EXTENSION
4-PIN CYL.
(USE PLUG
EXTENSION)

Python Compatible Products Service Procedure continued
It can be rekeyed using our 8491 Python keying kit and can be removed from the lock body with the
standard Python plug removal tool. With the plug in the unlocked position fully insert the removal
tool and then pull on the tool. If the plug doesn’t come out immediately, wiggle the tool and then pull,
the plug should be released and come out on the end of the tool.
In order to install the plug back into the
housing some further disassembly is
required.
At the far end of the plug there is a locking
member with a square recess in it. Use a
small screwdriver to push this locking
member down and disengage it from the
sliding bolt of the lock.
With the locking member pushed down, the sliding bolt can be removed from the lock completely.
While holding the locking member down, use a finger to hold it in place from the top while reinserting
the plug. The plug should have the removal tool in it and the rod extending from the back toward the
bottom of the lock when inserted
As you can see here, the locking member is spring loaded and can jump out of position. Reinstalling it
without distorting the spring takes a little patience and a pair of needle nose pliers.
If you remove the locking member from the lock body you must reinsert it
with the opening up and then, when over the recess for it in the body, pivot
the locking member so the opening faces the rear as shown here.
All keys for Python Mechanism products are the type with a plastic cover on
the head of the key. If you need code information, you can typically find it
stamped on the key head under the cover.
These are standard Master Lock key codes and you can see here that this one matches a code used in our
number 3 lock. All Python mechanism locks use our number 1 key and can be KA to existing keys as long
as they don’t have a number 7 depth in them.
The 379ATPY can be ordered KD or KA to the same codes that were available for the 377 coupler lock.
3489 LOCKING BALL MOUNT
This lock uses the standard Python plug for the key cylinder. It may be removed in
the unlocked position with the Python removal tool and rekeying may be
accomplished using the 8491 keying kit.
When servicing, if the lock operates roughly because of road dirt buildup or other
contaminants, remove the Python cylinder and press inward on the locking bolts
while impacting the rear of the mount on a hard surface. The entire lock will slide
out of the mount to allow cleaning and lubrication.
12

Cylinders
Master Lock Company makes ten basic cylinder sizes/types for use in our padlocks;
1. A small diameter cylinder for some of our laminated locks.
2. A four pin cylinder for our laminated locks.
3. A five pin cylinder for our laminated rekeyable locks
4. A six pin cylinder for our ProSeries ® locks.
5. A cylinder for our number 19 lock.
6. SFIC small format interchangeable core cylinders.
1. The small diameter cylinder is generally referred to as the number W7
cylinder and is used in various products where the available space is
limited. This cylinder is used in the number 7 laminated padlock, the
gun lock, etc., and is generally not accessible for rekeying. In those
cases where it can be rekeyed, it uses the same pins used in the first four
classes above. Those pins are available in our #291 pinning kit found
on page 28. See page 17 for service procedures.
2. The four pin cylinder is generally referred to as the number W1
cylinder and is used in the number 1, 3, 5 laminated padlocks, and
many other products. In many cases it is not accessible for rekeying,
but when it can be rekeyed you may use our #291 pinning kit.
Servicing procedures may be found on page 17.
3. The five pin cylinder is generally known as our number W27 cylinder
and is found in our laminated rekeyable locks such as the number 21,
24, 25, and 27. It may be rekeyed using our #291 pinning kit shown
on page 28.
There are times when you may want to use a four pin cylinder in a lock
designed for the five pin cylinder because of keyway compatibility.
That can be accomplished by using the 27-0334 plug actuator which
adapts the four pin cylinder to the five pin length.
4. The six pin cylinder is referred to by two different part numbers,
depending on the number of pin chambers that are pinned. When
pinned with only five pins, it is called the W6000 and if all six pins are
used it is called the W7000. This cylinder is found in our ProSeries ®
products and may also be rekeyed using our #291 pinning kit.
Effective mid-2001, Master Lock Company implemented a new six pin
cylinder and key. The cylinder changed from a crimp to an
E-clip which reflects tighter tolerances between the plug and shell. The
new key has a radiused blade bottom. This running change should have
no effect on key operation from old to new cylinder types.
13
7. Cylinders compatible with various door hardware
locks made by others.
8. Master Lock EDGE System
9. Python ®
10. Universal Pin

Cylinders continued
5. The W19 cylinder is only used in the number 19 lock and it is not
really accessible for rekeying without drilling the rivets. This cylinder
uses .125" diameter pins and a .025" increment. The shell is crimped
on both sides and does not allow the service technique typical on the
old style W1 cylinder. The only option available for rekeying would be
to use the holes on the bottom of the shell to remove pins from the
plug and replace them with new ones.
6. The Interchangeable Core cylinders are constructed to the SFIC
standards that you encounter with many other brands. Keying uses the
same techniques employed for those cylinders.
Master Lock offers IC cylinders keyed to existing key systems if you are
able to supply the combinations for the operating key, the TMK (Top
Master Key), and the Control key. Master Lock also has the ability to
recreate your entire key system, including all potential expansion, if you
can supply bitting combinations of all keys that have been used.
At present, Master Lock offers IC cylinders compatible with the A2 and A4 format from the factory. If you are equipped for
pinning SFIC cylinders, you can key the cylinders into an existing A3 system without difficulty. The listing below allows
construction of a correct SFIC cylinder part number when ordering from Master Lock.
CA604KD
Interchangeable Core Keying Specification
Keyway/Key Section KD – Keyed Different
Manufacturer’s Brand Name
A – Best A Keyway
B – Best B Keyway
C – Best C Keyway
D – Best D Keyway
E – Best E Keyway
F – Best F Keyway
G – Best G Keyway
H – Best H Keyway
J – Best J Keyway
K – Best K Keyway
L – Best L Keyway
M – Best M Keyway
Q – Best Q Keyway
W – Arrow 1C Keyway
X – Arrow 1D Keyway
Y – Master Lock Keyway
14
Number of pins
6 – six
7 – seven
KA – Keyed Alike
UN – Uncombinated
KDMK – KD Master Keyed
KAMK – KA Master keyed
Finish
04 – Satin Brass
26D – Satin Chrome

Cylinders continued
7. The door hardware cylinders are rekeyable using standard .115"
diameter pins. The plug is mounted to the shell with a ring retainer,
and use of a follower is recommended for rekeying. In order to
mount the cylinders in the lock, a cylinder retainer plug is placed
over the bible of the cylinder. The retainer plug has a threaded hole
used to mount it to the lock via the toe side shackle hole and the
socket screw. This cylinder also requires a special driver to be placed
between the cylinder tail and the lock actuator in order to function.
The listing below allows construction of a correct cylinder part
number when ordering from Master Lock.
D045KD
Door Hardware Cylinder Keying Specification
KD – Keyed Different
KA – Keyed Alike
Keyway KZ – Zero Bitted
Manufacturer’s Brand Name
Arrow 10
Corbin 59A1-2 01
Corbin 60 29
Corbin Russwin L4 07
Harloc SE-1* 02
Kwikset* 12
Lockwood 08
Lori L200* 02
Lori Locksmith 80 80
Loricentric 90 90
Master/Dexter 67* 32
Russwin 981/852 11
Russwin D1 30
Sargent LA-LC* 36
Sargent RA-RC* 70
Sargent S* 02
Sargent U* 02
Schlage C 04
Schlage E 34
Schlage P 28
Segal 9.265 27
Weiser*/Falcon 13
Weslock 33
Yale 8 03
Yale GA 15
Master Lock 200WP
EDGE ® System
(Available with 4 or 6 pins only)
8. The Master Lock EDGE System cylinders are available in both four and six pin versions. They are the
subject of utility patent 7,040,126. A secondary independent locking mechanism utilizing ball bearings on
each side of the keyway offers creation of virtual keyways for a key control system along with the special
actual keyway for the keys.
This cylinder has two 3/32” diameter ball bearings on each side of the keyway. The ball bearings are not
spring loaded and are not staked into place in the plug. Care should be observed when removing the plug
from the shell.
Plugs are normally drilled with only one hole for ball bearings on each side of the keyway and therefore
dedicated to the virtual keyway associated with those positions. Distribution of virtual keyways is controlled
geographically and the product and key blanks are only sold via locksmith distribution
15
Number of pins
4 – four**
5 – five
6 – six
KDMK – KD Master Keyed
KAMK – KA Masker keyed
UN – Uncombinated**
* Indicates a composite keyway that accepts more than one key section. Example: Keyway 02 accepts the
Sargent S, Sargent U, and Lori L200 keys.
**Exclusively available for the Master Lock EDGE Key Control System only.

Cylinders continued
NOTE: The Master Lock EDGE key control is compatible with the American Lock ® EDGE
Padlock and Door Key Control System. Cylinders for Door Hardware locks are only available as an
American Lock ® EDGE product and have a standard size shell for a mortise, rim and KIK
application. The plugs for those cylinders have a head that has a diameter typical of that found in door
hardware cylinders but the plug itself has the same .397” diameter found in the padlock cylinders.
That means the same 291 keying kit can be used for keying and all bittings and virtual keyways will
be the same as found in the padlock cylinder versions. All sizes and types of door hardware
compatible cylinders in the EDGE system will have 6 pin chambers, even the 1" mortise cylinders.
The Nickel-Silver keys introduced with this product are the standard for the American Lock ®
EDGE System cylinders to offer the added strength needed for this type of cylinder.
9. The Python cylinder has a removable plug that uses a disc tumbler mechanism and two inwardly
sprung sidebars for pick resistance. Supplied with the number 1 keyway, it is a rekeyable plug
that can be used in an increasing range of our automotive related products.
10.The Universal Pin cylinder. This cylinder is unique in its design and use. When
assembled at the factory it uses a pin tumbler that is both a bottom pin and a top pin
without the division between the two. This serrated pin is placed in the first four of five pin chambers and a standard driver
pin is placed in the last chamber. The serrations on the pin are made at .0155” increments and designed to be located where
a shear line might be created.
The UP product is a patented design that allows ‘setting’ a lock to a customer key without disassembly. There are some
simple steps to follow that ensure the customers key will operate.
a. Check the key for excessive wear. If worn, use a code cut key to set locks.
b. Insert and withdraw the key a few times to ensure that the pins are moving freely and seating on the key.
c. Place the 376 keying tool over the head of the key and in firm contact with the plug face.
d. Strike the keying tool once firmly with a hammer to shear all four pins at the shear line.
e. Strike the keying tool once more to ensure that the plug is fully seated and the newly created top pin in
the first chamber can extend into the groove around the plug and act as a plug retainer.
16

Cylinders continued
To assure that the plug is properly seated you can pinch the key to remove the first time. If it removes easily the plug is
properly seated. If it won’t withdraw, use the keying tool to seat the plug again.
The basic rules to follow with this product are to use a key with as little wear as possible to set the
lock, and to never set more than six locks with the same sample key.
When the pins are sheared they are not sheared exactly in a straight line. Because the diameter of the
pin chamber must allow free travel of the pin, it is larger than the pin. When the breaking force is
applied to the pin it tilts a little inside the pin chamber before it shears. That means that one side of
the pin is generally higher than the other.
As that higher edge passes under the pin chamber wall the pin is pushed into the bottom of the key
cut. Each time the key is used to set a lock this happens and makes a dent .0005” deeper than the cut
you started with. That is why the same sample key shouldn’t be used to set more than six locks.
The 376 keying tool is designed to assist in setting a lock to a key and other
devices not specifically designed for the UP series products should not be used.
Cylinder Service Procedure
Older style ProSeries ® cylinders and most other Master Lock cylinders may be serviced with
the metal follower in the 291 pinning kit or via the service holes in the bottom of the shell.
Some very specific steps must be followed when rekeying via the service holes but after the
first time the rekeying can be accomplished more quickly than using a follower.
This procedure will work on cylinders that have a crimp retainer as well as cylinders that use
a clip retainer, but will not work on EDGE cylinders.
1. Hold the cylinder with the service holes up.
2. Insert a working key and rotate 180°.
3. Remove existing bottom pins via service holes.
4. Rotate plug 90° Clockwise.
5. Remove old key and insert new one.
6. Rotate plug Counter-Clockwise 90°.
7. Insert new bottom pins to match new key combination.
8. Rotate plug 180° and remove key.
If you are rekeying and Master Keying the cylinder, complete disassembly with a follower is
recommended as that will allow the removal of extraneous master pins from the bible as well
as the plug.
17

Cylinder Service Procedure continued
All ProSeries ® locks are supplied with a six pin length cylinder for uniform keying capability. The ProSeries ® cylinder may be
combinated with 4, 5, or 6 pins to accommodate existing key codes.
Pin chambers in this cylinder are drilled from the shell into the bible.
Care should be exercised to avoid turning the plug 180° because, at that
point, the bottom pins will align with the service holes on the bottom of
the shell and could be lost.
1. The plug is held in the shell via a crimp in the end of the shell.
This crimp prevents removal of the plug from the shell unless you have
a Master Lock plug follower with a flat on it.
2. The bottom of the plug is undercut at the keyway to allow it to bypass
the crimp. The Master Lock plug follower is designed to fit the end of
the plug and automatically align with the crimp in the shell.
3. To remove the plug, turn it 90° counterclockwise and, with the special
plug follower, push the plug from the shell.
Once you have changed the pinning combination, insert the plug into
the shell.
Effective mid-2001, the crimp retainer was replaced with a new design
E-clip. To service the current cylinder, remove the E-clip and then follow
step 3 above. This running change replacement eliminated the crimped
retainer for the plug in all ProSeries ® 6000 and 7000 keyway cylinders.
This new design cylinder was also supplied with a new key design. The
new keys have radiused blade bottoms and the section stamping includes a
suffix “B” for ease of identification (see 23).
No. of Pins Keyway
Rekeyable Cylinders
Part Number by Cylinder Length
4 Pin 5 Pin 6 Pin
18
Keying
4 K1 294W1* 294W1* 296W1 KD
4 KWP4 294WP4* 294WP4* 296WP4 KD
5 K15 N/A 295W15 296W15 KD
5 K17 N/A 295W17 296W17 KD
5 K27 N/A 295W27 296W27 KD
5 K81 N/A 295W81 296W81 KD
5 K600A N/A 295W600 296W600A KD
6 K700A N/A N/A 296W700A KD
5 K6000 N/A N/A 296W6000 KD
6 K7000 N/A N/A 296W7000 KD
6 KWP6 N/A N/A 296WP6 KD
* Includes extension for a 4 pin cylinder in a 5 pin lock
NOTE: For KA or MK, insert that specification in front of the ‘W’ in the above part number.
For Zero Bitted, use suffix ‘KZ’ with above part number
Crimp
E-Clip

Servicing the BumpStop Mechanism
Cylinders containing the BumpStop mechanism pin have one different component than standard cylinders and may be rekeyed
when required. That one different component is the BumpStop top pin. It is longer than a typical
top pin and will only let the cylinder operate correctly when it is placed in a correct pin chamber.
When rekeying you
need to figure out
which pin chamber has the BumpStop pin in it
and be sure to change where it is for the new
combination of the new key.
For example, if you have a cylinder that was
keyed to the combination 42645, the
BumpStop pin would be in the second pin
chamber. If your new key has a combination of
54624, you would need to move the BumpStop
pin in the cylinder from the second to the fourth
pin chamber.
The table below indicates where the BumpStop pin may be used in the different types of locks.
The letter X in the table indicates a cut depth that isn't available in the product or a cut depth that
isn't compatible with the BumpStop pin.
Failure to move the pin will certainly make the cylinder vulnerable to a Bump Key attack and may make it impossible to even
insert some cut keys because of the extra length of the BumpStop driver pin.
D U M P T H E B U M P P I N
Cut #
0 X ®
1 ®
2 ®
3 ®
A good practice when keying a cylinder with BumpStop technology is to always dump the Bump Pin. That way when you
rekey it you can always put it into a valid location.
19
Master
Doorlock Master
Padlock
Padlock
KIK
American
Padlock
® X
® ® ®
® ® ®
X
STOP ®
X ®

Keying
Master Lock keys are coded from bow to tip and with a few exceptions, the increment used
is .0155". Master Lock keys will be encountered with two types of stamping on them.
Both direct and blind codes are stamped on the keys for different products. In the 291 pin
kit you will find the 290-0371 key gauge for decoding keys. The “B” series of keys, 6000B
and 7000B, use gauge 290-0373. For ProSeries ® products, use the top slot in the gauge.
Insert the key in the slot at the large end perpendicular to the gauge. Once inserted, pull the
key toward the smaller end of the slot until it stops. The number stamped on the gauge
directly below where the key stops is the cut depth for that cut position on the key. Repeat
the process for each cut position on the key to determine the actual combination of the key.
The cylinder being rekeyed may be set to an existing key combination or it may be zerobitted.
In either case, follow the plug out of the shell and discard the existing pins from the plug. If the cylinder was Master
Keyed, also remove any master pins that may have been retained in the shell. For the combination decoded, select the
appropriate length pin from the 291 pinning kit, and install in the appropriate pin chamber of the plug. Once all pins have
been installed, insert the plug into the shell and check for smoothness of operation. If you note roughness in the operation,
check the key to be sure it has been produced to the bitting specifications on page 25.
M A S T E R K E Y I N G
Most keying system software offers the option of providing a pinning chart. It is
advisable to use that option. If the option is not available,
the following example illustrates the procedure required to determine
the pinning of a master keyed cylinder.
With the example master key combination of 047345 at right, and the change key
combination of 405253, the first step is to figure out the bottom pins that you must
install in the cylinder, then the required master pins must be determined.
Bottom pins must be selected to allow operation of the shallowest cut
per position in the cylinder for either key. By comparing the two combinations,
select the shallowest cut for each cut position from either key. In our example we
have highlighted the shallowest cut depth,
and you can see that our bottom pins for the cylinder will be 005243. The master
pin sizes are determined by subtracting the shallowest cut depth from the deepest
cut depth for each pin position in the lock.
As noted in the example, the difference is 442112.
From this process, we know that in the first pin chamber we must have
a number zero bottom pin and a number 4 master pin for both keys
to operate. The illustration at the right shows the pinning for the master keyed
cylinder example. Depending upon the size of your key system, you may or may
not require master pinning in all of the pin chambers.
If you find that some cylinders require master pins in different pin chambers or if
different cylinders require different quantities of pin chambers to have master pins,
question the design of the system before proceeding. Having master pins in
different pin chambers may indicate that the system utilizes a Rotating Constant
Method of progression, which should be verified. Having different quantities of
master pins in different cylinders usually indicates faulty key system design, and you
should recommend that the system be replaced.
Use of the service holes is another optional method for rekeying if the cylinder hasn’t been, or doesn’t need to be master keyed.
While the steps are more numerous it often proves to be a quicker method than using a follower. The procedure is;
• Insert key and rotate 180° to remove existing bottom pins via the service holes
• Without removing the key, rotate the plug another 90°
• Remove the old key and insert the new one
• Rotate the plug back to the 180° position and install new bottom pins via the service holes
• Rotate the plug to the key pull position and remove key
20
Bottom Pins are bold.
Difference equals master pins
0 4734 5
4 0525 3
047345
405253
442112

Keying continued
EDGE K E Y C O N T RO L S Y S T E M
The new EDGE System has a secondary locking mechanism in the form of two ball bearings on each side of the keyway. The
nickel-silver keys have a dimple cut on each side of the new actual key section.
The ball bearings are required to align with a slot in the shell before the key can be removed and that means that the service
holes on the bottom of the shell cannot be used for rekeying as with other ProSeries ® cylinders. When using a follower during
rekeying care should be taken to retain the ball bearings in the plug because they are not staked in place and can be lost.
The technique of rolling your fingers along
the plug as it is removed has proven
effective. If ball bearings are lost, they can
be replaced with any standard 3/32" ball
bearing and Master Lock sells a package of
200 via part number 296-0200, they are also
included in the regular #291 keying kit.
These cylinders and keys are 100%
compatible with the American Lock EDGE mortise, rim and knob style cylinders. The American Lock EDGE products use a
nickel silver key for the added strength needed in door lock applications.
NOTE: If one or more of the ball bearings is left out of the cylinder during reassembly there is a danger of one of the top pins
entering the ball bearing hole and rendering the cylinder useless. Missing ball bearings also eliminate the key control potential in
the particular cylinder.
EDGE KEY CONTROL SYSTEM MASTER KEYING
The EDGE System products require application of one important rule regarding key system development. Number one master
pins cannot be used in any EDGE cylinder. Those cylinders each have two slots in the shell for the ball bearings and if a
number one master pin in the plug falls into one of those slots it will jam the cylinder preventing further rotation of the plug or
withdrawal of the key.
If you do not have the capability to produce keying systems that have eliminated the need for number one master pins, Master
Lock will generate a system for you with up to four levels of keying and a total of 20,000 CK’s in the system for a six pin
cylinder. Master Lock has a flat fee for this service but you must realize that a copy of the key system will not be retained by
Master Lock Co. A pinning matrix is also supplied with the keying system on a CD_ROM.
P Y T H O N P LU G
The Python plug may be removed from the lock housing with a service key if the plug is in the
unlocked position. If the plug isn’t in the unlocked position the differently sized tenons on the back of
the plug won’t let it be removed.
The Python plug also interacts with a circular actuator inside the lock body and that actuator is located
only by the plug. Before using the service key to remove the plug the cable should be removed from
the lock body and the body should be stored carefully when the plug has been pulled for rekeying to
avoid displacing the actuator. Displacement of the actuator effectively destroys the lock.
21

Keying continued
The disc tumblers are the snap in style and a special keying tool is available for rekeying. This tool is also supplied in the keying
kit for the Python. One major difference in the Python versus a standard laminated padlock is the number of depths available.
Normally Master’s number 1 key has the potential for 8 depths, (0 through 7),
but the Python only has 7, (0 through 6). The majority of locks using the
number 1 key don’t use a number 7 depth, but if you encounter one that does, it
cannot be keyed into the
Python plug.
Clearance
Spring
Holes
Tooth
The keying kit also includes a
key gauge, four different spare
plugs and two service keys.
The keying tool has a tooth on it that can be positioned on a disc tumbler to
remove it from the plug. The inner portion of the jaws on the tool is ideal for
pressing the tumblers into the plug.
Removal of a tumbler is best
accomplished as shown in the illustration at left. The tumbler will be ejected into
the clearance area of the tool and then may be exchanged for the desired tumbler.
The fifth tumbler is a steel retainer tumbler. This tumbler has a long side and a short
side and the longer side is the side that should be placed over the spring.
Once rekeying has been accomplished the service key can be used to replace the plug in the lock
body and the key should be pinched to allow removal without pulling the plug.
Product Category Model Numbers Plug Assembly
Python Adjustable
Locking Cables
8401D, 8402D, 8413 8401-0337
Key Cabinets 7122D – 7128D 8401-0338
Automotive Security
1470DAT, 2847DAT, 2854DAT,
8401-0339
2878DAT
Automotive Security
739DAT, 2989AT, 8287DAT,
8289AT
8401-0340
22

Improved Pro Series® Cylinders
C Y L I N D E R A N D K E Y E N H A N C E M E N T S
In August 2001, Master Lock made enhancements to our W6000 and W7000
cylinders used in the Pro Series padlocks. The tighter manufacturing
tolerances expand the number of key codes available while at the same time
reducing the risk of inadvertent key interchange.
The keys affected are the 6000 and 7000. Rounded bottom keys stamped
6000B and 7000B have replaced them.
New “B” keys and old keys can be used in the exact same padlock. Just be sure
to use care when duplicating the key. If you do not have the exact same blank
as the key you are duplicating, you must cut by code to avoid the new cut key
from being off by .0125" and unusable.
N E W K E Y S
ROUND O N T H E B OT TO M
Avoid duplicating an old style key onto a new
“B” style round-back blank. Cuts will be
.0125" too deep. Use codes below to cut.
Cut Root Depth
0 .2845"
1 .2690"
2 .2535"
3 .2380"
4 .2225"
5 .2070"
6 .1915"
7 .1760"
Notch
Box of 50 new 6000B Key Blanks
Order No. K6000BOX.
B
B
Notch
Box of 50 new 7000B Key Blanks
Order No. K7000BOX.
Rounded
Bottom
23
O L D K E Y S
FLAT O N T H E B OT TO M
Avoid duplicating a “B” round-back key onto
an old style blank. Cuts will be .0125" too
shallow. Use codes below to cut.
Original blanks no longer available.
Cut Root Depth
0 .271"
1 .256"
2 .240"
3 .225"
4 .209"
5 .194"
6 .178"
7 .163"
NEW Spool and Driver
Pins are Flat
No B and No Notch on Bottom
No B and No Notch on Bottom
Flat Flat
Bottom
New Tighter
Tolerance Plug
and Shell
New Flat Ended
Spool Pins
0296-0322
7000-0060 MO 10M 12/01
New E-Clip
0296-0324
New, Non-
Spool Driver
Pin in 5th Chamber
0296-0323
OLD Spool and Driver
Pins were Domed

Master Lock uses a wide range of keys and keyways. Below Below illustrates illustrates the the re relationship of keys to keyways and the corresponding
part numbers.
Four Pin Five Pin
K1
W1
Five Pin
K27
W27
Five Pin Six Pin
K6000
W6000
Discontinued
Keys and Keyways
K1RSV
W1RSV
K6000
W6000
K81
W81
6000B
K2
W2K
SAFETY
K400
W400
KWP4
WP4
K81KM
W81KM
LOCKOUT
K7000
W7000
Discontinued
24
K15
W15
K81RSV
W81RSV
K7000
W7000
7000B
K900
W900
K17
W17
KWP6
WP6
900

Bitting Specifications
Root Depth
Key Blank Key Blank
Spacing Stop Spacing Cut Used in Master Lock
Part Number Width 0 1 2 3 4 5 6 7 To First Cut To Cut
1K 0.281 0.2720 0.2565 0.2410 0.2255 0.2100 0.1945 0.1790 0.1635 0.187 0.125 1,2,3,4,5,6,11,77,33,34,35,36,37,39,425,475
2K 0.281 0.2720 0.2565 0.2410 0.2255 0.2100 0.1945 0.1790 0.1635 0.187 0.125 1MK.2MK,3MK,4MK,5MK,6MK,11MK
1RES 0.277 0.2770 0.2615 0.2460 0.2305 0.2150 0.1995 0.1840 0.1680 0.187 0.125
7K 0.212 0.2120 0.1965 0.1810 0.1655 0.1500 0.1345 0.1190 NA 0.132 0.125 7,8,90,716,719
7RES 0.208 0.2080 0.1925 0.1770 0.1645 0.1460 0.1305 0.1150 NA 0.132 0.125 7,8,90
15K 0.272 0.2720 0.2565 0.2410 0.2255 0.2100 0.1945 0.1790 0.1635 0.187 0.125 15
17K 0.272 0.2720 0.2565 0.2410 0.2255 0.2100 0.1945 0.1790 0.1635 0.187 0.125 17
19K 0.374 0.3720 0.3470 0.3220 0.2970 0.2720 0.2470 0.2220 0.1970 0.218 0.156 19
27K 0.283 0.2720 0.2565 0.2410 0.2255 0.2100 0.1945 0.1790 0.1635 0.187 0.125 21,24,25,27,31,101,220,230
52K 0.277 0.2720 0.2565 0.2410 0.2255 0.2100 0.1945 0.1790 0.1635 0.187 0.125 8179
25
81KR 0.283 0.2820 0.2665 0.2510 0.2355 0.2200 0.2045 0.1890 NA 0.187 0.125 50,81,82,1710,1714
81KM 0.283 0.2820 0.2665 0.2510 0.2355 0.2200 0.2045 0.1890 0.1735 0.187 0.125 81MK,82MK,1710MK,1714MK
81RES 0.283 0.2740 0.2585 0.2430 0.2275 0.2120 0.1965 0.1810 0.1655 0.187 0.125
120K 0.200 NA 0.1950 0.1750 0.1550 0.1350 NA NA NA 0.132 0.12 120
130K 0.270 0.2700 0.2400 0.2100 0.1800 0.1500 0.1200 NA NA 0.132 0.12 130,140
150K 0.270 0.2700 0.2400 0.2100 0.1800 0.1500 0.1200 NA NA 0.150 0.129 150,160
600K 0.308 0.2840 0.2684 0.2528 0.2372 0.2215 0.2059 0.1903 0.1747 0.159 0.125 220,230 w/American cylinder
700K 0.308 0.2840 0.2684 0.2528 0.2372 0.2215 0.2059 0.1903 0.1747 0.159 0.125 All Pro Series ® w/American cylinder
900K 0.272 0.2720 0.2565 0.2410 0.2255 0.2100 0.1945 0.1790 0.1635 0.187 0.125 Retail Contractor Grade
K2650 0.283 N/A 0.2637 0.2440 0.2240 0.2045 0.1850 N/A N/A 0.2830 0.125 2650 ADA Lock
6000K 0.283 0.2710 0.2555 0.2400 0.2245 0.2090 0.1935 0.1780 0.1625 0.187 0.125 All Pro Series ® 5 Pin cylinders
7000K 0.283 0.2710 0.2555 0.2400 0.2245 0.2090 0.1935 0.1780 0.1625 0.187 0.125 All Pro Series ® 6 Pin cylinders
Keys with Radiused Blade Bottom (stamped 6000B and 7000B) Effective August, 2001
6000K 0.290 0.2845 0.2690 0.2535 0.2380 0.2225 0.2070 0.1915 0.1760 0.187 0.125 All Pro Series ® 5 Pin cylinders
7000K 0.290 0.2845 0.2690 0.2535 0.2380 0.2225 0.2070 0.1915 0.1760 0.187 0.125 All Pro Series ® 6 Pin cylinders
WP4&6 0.290 0.2845 0.2690 0.2535 0.2380 0.2225 0.2070 0.1915 0.1760 0.187 0.125 All ML ® System cylinders

ProSeries® Actuators and Drivers
AC T UATO R S
As noted in the exploded views, all ProSeries ® locks use an actuator mechanism
that causes the ball bearings to lock or unlock the shackle. Typically ProSeries ®
locks are supplied with a NKR, Non Key Retaining, function actuator. There are
five different variations of an NKR actuator you may encounter as shown here.
The two actuators on the right are the original 8 o’clock position type used in the
Weather Tough ® , Shrouded, Solid Body Brass and Solid Body Aluminum locks
and also the Door Hardware compatible Solid Steel Body locks.
The two actuators on the left are the newer 12 o’clock versions used in all current
Solid Body locks except the Door Hardware compatible Solid Steel locks. The
middle actuator is used only in the 6230 lock.
The differences are in the size of the actuator and the location of the
projection on the spring washer. The position of that projection inside the
lock is critical to lock operation. Care should be taken to note the position
when disassembling a lock so that it may be reassembled correctly. In the
picture, the actuator on the left is called a 12 o’clock style and the one on
the right is called the 8 o’clock style.
In 2010 the shape of the actuators was changed for the Pro-Series® locks to
a die-cast version. This die cast version spreads force from the ball bearings
over a wider surface to inhibit shackles from pulling out in the unlocked
position.
There are three different actuators to provide the NRK, Non Removable
Key, function and they are show here. Special care should be taken to
position them correctly within the lock during assembly.
D R I V E R S
The door hardware locks require a driver to allow the door hardware cylinder
to drive the actuator. There are four driver types available and they are
shown on the right. Shown is the distinctive feature of the driver that
engages the cylinder.
Positioning the driver on the cylinder should always be done to ensure that
the orientation of the driver forms the assembly profile at the right.
26
6841-0421
6841-0421
Lori
6831-0421
12 O’Clock
6831-0421
6830-0422
Medeco
6121-0425
6121-0422
Schlage
8 O’Clock
6121-0423
6121-0423
6121-0426
Lockwood
Australia
6830-0421
6830-0421

ProSeries® Actuators and Drivers continued
The Lori cylinders are available from Master Lock as part of the lock assembly and will be supplied with the 298-0626 driver.
If you are using a Medeco 20-20000 or 20W20000 cylinder you should use a number 298-0627 driver. For all Schlage cylinders
and the ASSA 65611 cylinder for the padlock you can use a 298-0628 driver. The number 298-0625 driver is used to adapt an
Australian Lockwood cylinder.
Medeco also offers a cylinder for the padlock that can be used without a driver. Use a 51-0600 or a 51W0600 cylinder for that
option, but realize that the same cylinder will not be adaptable to a door hardware lockset.
Lori
Cylinder
Driver
298-0626
Lori
Cylinder
1539
Lori
Key
Cylinder
Retainer
Plug
298-0629
Medeco
Cylinder
Driver
298-0627
Medeco
Cylinder
20-20000
Medeco
Key
®
Cylinder
Retainer
Plug
298-0629
27
Schlage
Cylinder
Driver
298-0628
Schlage
Cylinder
Schlage
Key
®
Also for
ASSA 65611,
GMS,
ILCO 1599,
Primus
Everest
Cylinder
Retainer
Plug
298-0629
Lockwood
Australia
Cylinder
Driver
298-0625
Lockwood
Australia
Cylinder
®
Lockwood
Australia
Key
Cylinder
Retainer
Plug
298-0629

Tools
The 291 Pin Kit includes all tumbler and driver pins needed to repin Master Lock rekeyable padlocks (not IC or Door
Hardware pins though). It also includes several tools to assist in rekeying the cylinder. The 8491 keying kit includes all tumblers
needed to rekey the Python cylinder plug. It also includes a special keying tool, service keys and a key gauge.
Parts included in 291 Rekeying Kit
Plug Extender
27-0334
Key Cut Gauges
290-0371 for all keys but 6000B and 7000B
290-0373 for 6000B and 7000B keys
Cylinder Assembly Tool
290-0372 Follower
APKG0060612 EDGE Follower
Hex Wrenches
1/16" American Lock ® EDGE Wrench
3/32" – For Rekeyables
7/64" – For Rekeyables
1.5mm for 6270 & 6271 not included (purchase locally if
needed)
Trap Doors
21-0372 for 21, 24, 101 padlocks
27-0371 for 27 padlock
6121-0420 for many Pro Series
6830-0023 for many Pro Series
Also includes a wide assortment of retaining nuts, springs and pins for
rekeyable padlocks and ball bearings for EDGE 291 Rekeying Kit
Key Gauge
Hex Wrench
EDGE
Key Control products.
Follower
Parts included in 8491 Rekeying Kit
Key Cut Gauge
290-0371 for all keys but 6000B and 7000B
Rekeying Tool
8401-0371
Plug Assemblies
8401-0337, 8401-0338, 8401-0339, 8401-0340
Driver Springs
8401-0369
Service Keys
8401-0370
Disc Tumblers
No. 0 – 8401-0360 No. 3 – 8401-0363 No. 6 – 8401-0366
No. 1 – 8401-0361 No. 4 – 8401-0364
No. 2 – 8401-0362 No. 5 – 8401-0365
Cylinder Retaining Disc
8401-0368
28
8491 Python
Rekeying Kit
Service
Keys
Key Gauge
Cylinder Assembly Tool
Rekeying Tool

Lock Lubricants
Master Lock Lock Lubricant can be used for lubricating the various lock
components. The lubricants contain PTFE formulations that can be used
for padlocks, door locks, automotive, marine, and multipurpose
applications. The effective operating temperature range is -40°F to 500°F
and helps de-ice pre-lubricated locks.
Two aerosol sizes are available that contain a “dry” lubricant formula that
lubricates without collecting dirt or dust. The 2305 aerosol is a 5.25 oz.
size convenient for carrying to jobs and the 2311 aerosol is an 11 oz. size
ideal for keeping in the shop.
Recommended Padlock
Cleaning & Lubrication
Over time, dust particles and chemicals in the air settle
on and in the padlock. They can then create friction
inside the precision locking and keying components and
impede the opening and closing of the padlock. Annual
cleaning is recommended. In particularly dusty or
corrosive environments, clean every three months.
Recommended Directions:
• Flush grease and dirt from the padlock as needed.
• Apply Master Lock ® Lock Lubricant to the keyway
and shackle holes, using a very light spray. “Psst”, not
“Psssssssssssssssst”!
• Insert key, open and close padlock several times to
distribute lubricant.
Available Late
Fall 2010
29
Apply lubricant
to shackle heel
Average number
of times opened
per day
1 to 50
51 to 100
Apply lubricant
to shackle toe
Apply lubricant
to keyway
Dry Lubricant
Application Schedule
(Normal Environment)
Once per year
Twice per year

Terminology
When making a definition of a term, the following rules were
applied to the term:
1. Is the term listed in a standard dictionary?
2. Is the definition there the same meaning used in
our industry?
A standard pocket dictionary can be obtained easily and
on short notice from a variety of stores that have a
pocket book display. If the answer to either of the
questions above is no, then the definition of the term
may be found here.
-Aactual
key section n. the exact cross sectional
configuration of a key blade as viewed from the bow
toward the tip
actuator n. a device, usually connected to a cylinder,
which, when activated, may cause a lock mechanism
to operate
ADA abb. Americans with Disabilities Act
adjustable mortise cylinder n. any mortise cylinder
whose length can be adjusted for a better fit in doors
of varying thickness
all-section key blank n. the key section which enters
all keyways of a multiplex key system
ALOA abb. Associated Locksmiths of America, Inc.
associated change key n. a change key which is
related directly to particular master key(s) through the
use of constant cuts
associated master key n. a master key which has
particular change keys related directly to its
combination through the use of constant cuts
ASTM abb. American Society for Testing
and Materials
auxiliary lock n. any lock installed in addition to the
primary lockset
-Bball
locking adj. a method of locking a padlock
shackle into its case using ball bearing(s) as the bolt(s)
battery eliminator n. an electric device designed
to provide energy to equipment normally requiring
batteries for operation
bible n. that portion of the cylinder shell which
normally houses the pin chambers, especially those
of a key-in-knob cylinder or certain rim cylinders
bicycle padlock n. a padlock with sufficient shackle
clearance to secure a bicycle
bi-directional cylinder n. a cylinder which may
be operated in a clockwise and counterclockwise
direction by a single key
binary cut key n. a key whose combination only
allows for two possibilities in each bitting position:
cut/no cut
binary type cylinder or lock n. a cylinder or lock
whose combination only allows for two bitting
possibilities in each bitting position
bit n. the part of the key which serves as the blade,
usually for use in a warded or lever tumbler lock
v. to cut a key
bit key n. a key with one or more projecting bits
bitting n. 1. the number(s) which represent(s)
the dimensions of the key 2. the actual cut(s)
or combination of a key
bitting depth n. the depth of a cut which is made
into the blade of a key
bitting list n. a listing of all the key combinations
used within a system. The combinations are usually
arranged in order of the blind code, direct code,
and/or key symbol.
bitting position n. the location of a key cut
blade n. the portion of a key which may contain the
cuts and/or millings
blank adj. uncut, see also “key blank”
blind code n. a designation, unrelated to the bitting,
assigned to a particular key combination for future
reference when additional keys or cylinders may
be needed
block master key n. the one pin master key for all
combinations listed as a block in the standard
progression format
BMK abb. block master key
bolt n. any movable projection which blocks the
movement of one object relative to another
bottom of blade n. the portion of the blade opposite
the cut edge of a single bitted key
30
A definition must meet the following rules:
1. It must describe the subject of the term
without graphics.
2. It must describe ONLY the subject of the term.
3. The term should not be used in the definition.
If you have a technical objection to any definition,
please bring it to the attention of a member of the LIST
Council for review.
Used by permission. Copyright © 1989, 1990, 1995, 1996,
1997 LIST Council
bottom pin n. usually a cylindrical shaped tumbler
which may be conical, ball shaped or chisel pointed
on the end which makes contact with the key
bow n. the portion of the key which serves as a grip
or handle
bow stop n. a type of stop located near the key bow
box of wards n. a complete unit of intricate wards
installed in or on a lock case
bridge ward n. a center ward attached to the interior
of a lock by means of a bracket
broach n. a tool used to cut the keyway into the
cylinder plug v. to cut the keyway into a cylinder
plug with a broach
build-up dimension n. 1. the distance between
two different shear lines, as expressed in units of the
manufacturer's increment or as an actual
measurement 2. the dimension of the build-up pin
required in a particular chamber, which will allow one
key to operate at the plug shear line and a different
key to operate at a different shear line
build-up pin n. the additional element of a pin stack
required to allow operation at different shear lines in
a cylinder
bump key n. a lock picking key with uniform
steeples between cuts that is forced further into the
lock via impact
by-pass tool n. a device that neutralizes the security
of a locking device, or its application hardware,
often taking advantage of a design weakness
-Ccam
n. 1. a lock or cylinder component which
transfers the rotational motion of a key or cylinder
plug to the bolt works of a lock 2. the bolt of a
cam lock
cam lock n. a complete locking assembly in the form
of a cylinder whose cam is the actual locking bolt
cap n. 1. a spring cover for a single pin chamber
2. a part which may serve as a plug retainer and/
or a holder for the tailpiece v. to install a cap

Terminology
capping block n. a holding fixture for certain interchangeable
cores which aids in the installation of
the caps
case n. the housing or body of a lock
case ward n. any ward directly attached to or
projecting from a lock case
chamber n. any cavity in a cylinder plug and/or shell
which houses the tumblers
change key n. a key which operates only one
cylinder or one group of keyed alike cylinders in
a keying system, see also “reset key” definition 1
changeable bit key n. a key which can be
recombinated by exchanging and/or rearranging
portions of its bit or blade
Chubb shackle n. a hinged shackle with a pierced
hole for the bolt in its movable end
CK abb. 1. change key 2. control key
clevis n. a device to permanently attach a chain
to a padlock
clipper n. a hand held key bitting punch,
often incorporating a triggerlike handle
closed gated adj. pertaining to a lever tumbler
whose gate is pierced into the body of the tumbler.
The lever(s) surround the fence in both the locked
and unlocked positions.
clutch n. that part of a profile cylinder which
transfers rotational motion from the inside or outside
element to a common cam or actuator
CML abb. the title "Certified Master Locksmith"
as awarded by ALOA
code n. a designation assigned to a particular key
combination for reference when additional keys or
cylinders may be needed. See also, “blind code”,
“direct code”, and “key symbol”
code key n. a key cut to a specific code rather than
duplicated from a pattern key. It may or may not
conform to the lock manufacturer's specifications
code original key n. a code key which conforms to
the lock manufacturer's specifications
combinate v. to set a combination in a lock,
cylinder, or key
combination n. the group of numbers which
represent the bitting of a key and/or the tumblers
of a lock or cylinder
compensate drivers v. to select longer or shorter top
pins, depending on the length of the rest of the pin
stack, in order to achieve a uniform pin stack height
complementary keyway n. usually a disc tumbler
keyway used in master keying. It accepts keys of
different sections whose blades contact different
bearing surfaces of the tumblers.
composite keyway n. a keyway which has been
enlarged to accept more than one key section,
often key sections of more than one manufacturer
compound bitted key n. a key with at least one
compound cut
compound cut n. a bitting which has another
bitting dimension within its dimensions
constant cut n. any bitting(s) which are identical
in corresponding positions from one key to another
in a keying system. They usually serve to group these
keys together within a given level of keying, and/
or link them with keys of other levels. See also
“rotating constant”
construction core n. an interchangeable or
removable core designed for use during the
construction phase of a building. The cores are
normally keyed alike and, upon completion of
construction, they are to be replaced by the
permanent system's cores.
control chamber n. in an interchangeable or
removable core, any chamber which has a control
shear line, which is different from the operating
shear line
control cut n. any bitting which operates the
retaining device of an interchangeable or
removable core
control key n. 1. a key whose only purpose is to
remove and/or install an interchangeable or removable
core 2. a bypass key used to operate and/or reset
some combination type locks 3. a key which allows
disassembly of some removable cylinder locks
control lug n. that part of an interchangeable or
removable core-retaining device which locks the core
into its housing
control shear line n. the shear line which allows
operation of the control lug of an interchangeable or
removable core
control sleeve n. the part of an interchangeable
or removable core retaining device which surrounds
the plug
controlled cross keying a condition in which two
or more different keys of the same level of keying
and under the same higher level key(s) operate one
cylinder by design; e.g., XAA1 operated by AA2
(but not XAA1 operated by AB1)
Note: This condition could severely limit the
security of the cylinder and the maximum expansion
of the system when (1) more than a few of these
different keys operate a cylinder, or (2) more than
a few differently cross keyed cylinders per system
are required.
31
core n. a complete unit, often with a “figure eight”
shape, which usually consists of the plug, shell,
tumblers, springs, plug retainer and spring cover(s).
It is primarily used in removable and interchangeable
core cylinders and looks.
CPL abb. the title "Certified Professional
Locksmith" as awarded by ALOA
CRL abb. the title "Certified Registered Locksmith"
as awarded by ALOA
cross keying n. the deliberate process of
combinating a cylinder (usually in a master key
system) to two or more different keys which would
not normally be expected to operate it together.
See also “controlled cross keying” and “uncontrolled
cross keying."
cruciform adj. of or pertaining to a key section or
keyway which usually resembles a plus sign (+) or the
letter "X"
cut v. to make cuts into a key blade, see also
“key cut(s)”
cut edge n. the portion of the key blade which
contains the cuts
cut key n. a key which has been bitted
or combinated
cut root n. the bottom of a key cut
cut root shape n. the shape of the bottom of
a key cut. It may have a flat or radius of a specific
dimension, or be a perfect "V"
cutter n. the part of a key machine which makes the
cuts into the key blank
cylinder n. a complete operating unit which
usually consists of the plug shell, tumblers, springs,
plug retainer, a cam/tailpiece or other actuating
device, and all other necessary operating parts
cylinder blank n. a dummy cylinder which has
a solid face and no operating parts
cylinder collar n. a plate or ring installed under
the head of a cylinder to improve appearance and/
or security
cylinder guard n. a protective cylinder
mounting device
cylinder key n. a broad generic term including
virtually all pin and disc tumbler keys
-Ddeadbolt
n. a bolt, which requires a deliberate
action to extend, and which resists end pressure
in the unlocking direction when fully extended
deadlock n. a lock which incorporates a deadbolt

Terminology
deadlocking adj. pertaining to any feature which,
when fully engaged, resists attempts to move the
latch or bolt in the unlocking direction through
direct pressure
declining step key n. a key whose outs are
progressively deeper from bow to tip
decode v. to determine a key combination by
physical measurement of a key and/or cylinder parts
decoder gauge n. a measuring device which helps
determine the combination of a lock or cylinder
without removing the tumblers
depth key set n. a set of keys used to make a code
original key on a key duplicating machine to a lock
manufacturer's given set of key bitting specifications.
Each key is cut with the correct spacing to one
depth only in all bitting positions, with one key for
each depth.
derived series n. a series of blind codes and
bittings which are directly related to those of another
bitting list
direct code n. a designation assigned to a particular
key which includes the actual combination of the key
disc tumbler n. 1. a flat tumbler which must be
drawn into the cylinder plug by the proper key so
that none of its extremities extends into the shell
2. a flat, usually rectangular tumbler with a gate
which must be aligned with a sidebar by the
proper key
double-acting lever tumbler n. one that must
be lifted a precise amount, neither too little nor too
much to allow movement of a bolt
double bitted key n. a key bitted on two opposite
surfaces
double pin v. to place more than one master pin in
a single pin chamber
drilled key n. a type of bit key with a hole drilled
into the shank from the tip
driver spring n. a spring placed on top of the pin
stack to exert pressure on the pin tumblers
drop n. a pivoting or swinging dust cover,
see also “increment”
dummy cylinder n. a non-functional facsimile of
a rim or mortise cylinder used for appearance only,
usually to conceal a cylinder hole
duplicate v. to copy, see also “duplicate key”
duplicate key n. any key reproduced from a
pattern key
dustproof cylinder n. a cylinder designed to prevent
foreign matter from entering either end of the keyway
-Eeffective
plug diameter n. the dimension obtained
by adding the root depth of a key cut to the length
of its corresponding bottom pin which establishes
a perfect shear line. This will not necessarily be the
same as the actual plug diameter.
ejector hole n. a hole found on the bottom of
certain interchangeable cores under each pin chamber.
It provides a path for the ejector pin.
ejector pin n. a tool used to drive all the elements
of a pin chamber out of certain interchangeable cores
electrified lockset n. a lock which is
controlled electrically
end ward n. a ward which prevents complete
insertion and/or rotation of an incorrect key by
forming an obstruction to the end of the key
end ward cut n. any cut made into a key to bypass
an end ward
-Ffactory
original key n. the out key furnished by the
lock manufacturer for a lock or cylinder
fail-safe adj. a feature of a security device designed
to release, for safety purposes, during a power loss
fence n. 1. a projection on a lock bolt which
prevents movement of the bolt unless it can enter
gates of properly aligned tumblers, see also “sidebar”
2. any locking element other than a sidebar or
shackle designed to enter a tumbler's gate
file cabinet lock n. 1. any lock used on a file
cabinet 2. a plunger lock cylinder for a gang lock
normally used in a file cabinet
finish n. a material, coloring and/or texturing
specification
first generation duplicate n. a key which was
duplicated using a factory original key or a code
original key as a pattern
first key n. any key produced without the use of
a pattern key
five column progression n. a process wherein key
bittings are obtained by using the cut possibilities in
five columns of the key bitting array
five pin master key n. a master key for all
combinations obtained by progressing five
bitting positions
flat type key n. a key which is completely flat
on both sides, usually used for warded or lever
tumbler locks
flexible head mortise cylinder n. an adjustable
mortise cylinder which can be extended against spring
pressure to a slightly longer length
32
foot n. the cam portion of the trunnion assembly in
some lever tumbler locks
four column progression n. a process wherein key
bittings are obtained by using the cut possibilities in
four columns of the key bitting array
four pin master key n. a master key for all
combinations obtained by progressing four
bitting positions
frangible shackle n. a padlock shackle designed
to be broken easily
frangible shackle padlock n. a padlock equipped
with an easily broken shackle
-Ggate
n. a notch cut into the edge of a tumbler
to accept a fence or sidebar
GGGMK abb. great great grand master key
GGGMK'D abb. great great grand master keyed
GGM abb. great grand master key
GGMK abb. great grand master key
GGMK'D abb. great grand master keyed
GM abb. grand master key
GMK'D abb. grand master keyed
graduated drivers n. a set of top pins of different
lengths. Usage is based on the height of the rest of the
pin stack, in order to achieve a uniform pin stack
height. See also “compensate drivers”
grand master key n. the key which operates two
or more separate groups of locks, which are each
operated by a different master key
grand master key system n. a master key system
which has exactly three levels of keying
grand master keyed adj. of or pertaining to a lock or
cylinder which is or is to be keyed into a grand master
key system
great grand master key n. the key which operates
two or more separate groups of locks which are each
operated by a different grand master key
great grand master key system n. a master key
system which has exactly four levels of keying
great grand master keyed adj. of or pertaining to a
lock or cylinder which is or is to be keyed into a great
grand master key system
great great grand master key n. the key which
operates two or more separate groups of locks which
are each operated by different great grand master keys

Terminology
great great grand master key system n. a master
key system which has five or more levels of keying
great great grand master keyed adj. of or pertaining
to a lock or cylinder which is or is to be keyed into a
great great grand master key system
guide n. 1. that part of a key machine which
follows the cuts of a pattern key or template during
duplication 2. that part of a flat key lever lock
which connects the nose to the foot and supports the
key blade
-Hhand
change adj. pertaining to a combination
lock in which the wheels must be removed in order
to change the combination
handed adj. pertaining to hardware which is
manufactured only for application on doors with
a specific orientation
hardware schedule n. a listing of the door hardware
used on a particular job it includes the types of
hardware, manufacturers, locations, finishes, and sizes.
It should include a keying schedule specifying how
each locking device is to be keyed.
hasp n. a hinged metal strap designed to be passed
over a staple and secured in place
heel & toe locking n. describes a padlock which has
locking dogs at both the heel and toe of the shackle
heel (of a padlock shackle) n. the part of a padlock
shackle which is retained in the case when in the
unlocked position
HGM abb. horizontal group master key
high security cylinder n. a cylinder which offers
a greater degree of resistance to any or all of the
following: picking, impressioning, key duplication,
drilling or other forms of forcible entry
high security key n. a key for a high security
cylinder
hinged shackle n. a shackle whose heel is
permanently mounted to the padlock case in a
manner which allows the shackle to pivot to open
Hobbs shackle n. a hinged shackle with a notch
for the bolt in its movable end
holding fixture n. a device which holds cylinder
plugs, cylinders, housings, and/or cores to
facilitate the installation of tumblers, springs
and/or spring covers
hollow driver n. a top pin hollowed out on one end
to receive the spring, typically used in cylinders with
extremely limited clearance in the pin chambers
hook bolt n. a lock bolt shaped in the general
outline of a hook. Normally used on sliding doors
or where spreading of the frame and door is a
possible attack.
horizontal group master key n. the two pin master
key for all combinations listed in all blocks in a line
across the page in the standard progression format
horn n. in a non-cylinder lock, the housing which
surrounds the nose and extends through the door
or drawer
horn plate n. the cover of a lever tumbler lock case
to which the horn is attached
housing n. that part of a locking device which is
designed to hold a core
hub n. a lock component, which redirects rotational
motion from a spindle or shaft to linear movement
of a latch or bolt
-I-
IC abb. interchangeable core
impression n. the mark made by a tumbler on its
key cut v. to fit a key by the impression technique
impression technique n. a means of fitting a key
directly to a locked cylinder by manipulating a blank
in the keyway and cutting the blank where the
tumblers have made marks
incidental master key n. a key cut to an unplanned
shear line created when the cylinder is combinated
to the top master key and a change key
increment n. a usually uniform increase or decrease
in the successive depths of a key cut which must be
matched by a corresponding change in the tumblers
index (of a combination lock dial) n. the mark
outside the dial ring of a combination lock used as a
reference point
individual key n. an operating key for a lock or
cylinder which is not part of a keying system, see also
“change key” definition 1
interchangeable core n. a key removable core which
can be used in all or most of the core manufacturer's
product line. No tools (other than the control key)
are required for removal of the core.
-Kk
sym. symbol for "keys" used after a numerical
designation of the quantity of the keys requested to
be supplied with the cylinders; e.g., lk, 2k, 3k, etc.
it is usually found in hardware/keying schedules.
KA abb. keyed alike
KA1, KA2, etc. symbol which indicates that all
cylinders so designated are or are to be operated by
the same key(s). The numerical designation indicates
the keyed alike group or set.
KA/2, KA/3, etc. symbol used to indicate the
quantity of locks or cylinders in keyed alike groups.
These groups are usually formed from a larger
quantity; e.g., 30 cylinders KA/2.
33
KBA abb. key bitting array
KD abb. keyed different
key n. a properly combinated device which is,
or most closely resembles, the device specifically
intended by the lock manufacturer to operate
the corresponding lock
key bitting array n. a matrix (graphic) display of all
possible bittings for change keys and master keys as
related to the top master key
key bitting punch n. a manually operated device
which stamps or punches the cuts into the key blade,
rather than grinding or milling them
key bitting specifications n. pl. the technical data
required to bit a given (family of) key blank(s) to the
lock manufacturer's dimensions
key blank n. any material manufactured to the
proper size and configuration which allows its entry
into the keyway of a specific locking device. A key
blank has not yet been combinated or cut.
key change adj. referring to a lock in which the
combination can be changed through the use of a
special key or tool without disassembling the lock
key changeable adj. of or pertaining to a lock or
cylinder which can be recombinated without
disassembly, by the use of a key. The use of a tool may
also be required.
key coding machine n. a key machine designed for
the production of code keys. It may or may not also
serve as a duplicating machine.
key control n. 1. any method or procedure
which limits unauthorized acquisition of a key and/
or controls distribution of authorized keys
2. a systematic organization of keys and key records
key cut(s) n. the portion of the key blade which
remains after being cut and which aligns the
tumbler(s)
key cut profile n. the shape of a key cut,
including the cut angle and the out root shape
key duplicating machine n. a key machine which
is designed to make copies from a pattern key
key gauge n. a usually flat device with a cutaway
portion indexed with a given set of depth or spacing
specifications. It is used to help determine the
combination of a key.
key-in-knob cylinder n. a cylinder used in a key-inknob
lockset
key interchange n. an undesirable condition, usually
in a master key system, whereby a key unintentionally
operates a cylinder or lock

Terminology
key machine n. any machine designed to cut
keys, See also "key coding machine" and
"key duplicating machine."
key manipulation n. manipulation of an incorrect
key in order to operate a lock or cylinder
key milling n. the grooves machined into the length
of the key blade to allow its entry into the keyway
key override n. a provision allowing interruption or
circumvention of normal operation of a combination
lock or electrical device adj. of or pertaining to such
a provision, as in "key override cylinder"
key override cylinder n. a lock cylinder installed
in a device to provide a key override function
key pull(s) n. a lock specification which indicates
by quantity and orientation the position(s) in which
a key may be withdrawn
key pull position n. any position, of the cylinder
plug at which the key can be removed
key records n. pl. records which typically include
some or all of the following: bitting list, key bitting
array, key system schematic, end user, number of
keys/cylinders issued, names of persons to whom keys
were issued, hardware/keying schedule
Key Records Department n. the department which
is responsible for generating and issuing all lock and
key combinations and maintaining records of them
key retaining adj. 1. of or pertaining to a lock
which must be locked before its key can be removed.
2. of or pertaining to a cylinder or lock which may
prevent removal of a key without the use of an
additional key and/or tool
key section n. the exact cross sectional configuration
of a key blade as viewed from the bow toward the tip
key symbol n. a designation used for a key
combination in the standard key coding system, e.g.,
A, AA, AA1, etc.
key system schematic n. a drawing with blocks
utilizing keying symbols, usually illustrating the
hierarchy of all keys within a master key system.
It indicates the structure and total expansion of
the system.
keyed adj. 1. combinated 2. having provision for
operation by key
keyed alike adj. of or pertaining to two or more
looks or cylinders which have or are to have the same
combination. They may or may not be part of a
keying system.
keyed different adj. of or pertaining to a group
of locks or cylinders, each of which is or is to be
combinated differently from the others. They may
or may not be part of a keying system.
keyed random adj. of or pertaining to a cylinder
or group of cylinders selected from a limited
inventory of different key changes. Duplicate bittings
may occur.
keyhole n. the opening through which a noncylinder
key must pass to enter a lock
keying n. any specification for how a cylinder
or group of cylinders are or are to be combinated
in order to control access
keying conference n. a meeting of the end user
and the keying system supplier at which the keying
and levels of keying, including future expansion,
are determined and specified
keying kit n. a compartmented container which
holds an assortment of tumblers, springs and/or other
parts
keying schedule n. a detailed specification of the
keying system listing how all cylinders are to be
keyed and the quantities, markings, and shipping
instructions of all keys and/or cylinders to
be provided
keying symbol n. a designation used for a lock
or cylinder combination in the standard key coding
system; e.g., AA1, XAA1, XlX, etc.
keyway n. 1. the opening in a lock or cylinder
which is shaped to accept key bit or blade of a proper
configuration 2. the exact cross sectional
configuration of a keyway as viewed from the front.
It is not necessarily the same as the key section.
keyway ward n. a ward which prevents entry of an
incorrect key into a cylinder or lock
KR abb. 1. keyed random 2. key retaining
KWY abb. keyway
-Llaminated
padlock n. a padlock whose case is
constructed of separate plates usually riveted together
layout tray n. a compartmented container used to
organize cylinder parts during keying or servicing
levels of keying n. pl. the divisions of a master key
system into hierarchies of access, as shown in the
following tables. Note: the standard key coding
system has been expanded to include key symbols for
systems of more than four levels of keying.
TWO LEVEL SYSTEM
Level of
Keying
Key Name ABB. Key Symbol
Level II master key MK AA
Level I change key CK 1AA, 2AA,
etc.
34
THREE LEVEL SYSTEM
Level of Key Name ABB. Key Symbol
Keying
Level III grand GMK A
master key
Level II master key MK AA, AB, etc.
Level I change key CK AA1, AA2,
etc.
FOUR LEVEL SYSTEM
Level of Key Name ABB. Key Symbol
Keying
Level IV great grand GGMK GGMK
master key
Level III grand master GMK A, B, etc.
key
Level II master key MK AA, AB, etc.
Level I change key CK AA1, AA2,
etc.
FIVE LEVEL SYSTEM
Level of Key Name ABB. Key Symbol
Keying
Level V great great GGGMK GGGMK
grand master
key
Level IV great grand GGMK A, B, etc.
master key
Level III grand master GMK AA, AB, etc.
key
Level II master key MK AAA, AAB,
etc.
Level I change key CK AAA1,
AAA2, etc.
SIX LEVEL SYSTEM
Level of Key Name ABB. Key Symbol
Keying
Level VI great great GGGMK GGGMK
grand master
key
Level V great grand GGMK A, B, etc.
master key
Level IV grand master GMK AA, AB, etc.
key
Level III master key MK AAA, AAB,
etc.
Level II sub-master SMK AAAA,
key AAAB, etc.
Level I change key CK AAAA1,
AAAA2, etc.

Terminology
lever pack n. a set of lever tumblers
lever tumbler n. a flat, spring-loaded tumbler
which usually pivots on a post. It contains a gate
which must be aligned with a fence to allow
movement of the bolt.
loading tool n. a tool which aids installation
of cylinder components into the cylinder shell
lock n. any device which prevents access or use
by requiring special knowledge or equipment
lock bumping n. a picking technique that utilizes a
bump key being forcefully impacted into the keyway
lock service package n. a kit offered by the
manufacturer or distributor of a product, which
contains what he deems required to properly service
the product
locker lock n. a cabinet lock designed specifically for
use on lockers
lockout n. any situation in which the normal
operation of a lock or cylinder is prevented
lockout key n. a key made in two pieces. One piece
is trapped in the keyway by the tumblers when
inserted and blocks entry of any regular key.
The second piece is used to remove the first piece.
locksmith n. a person with the knowledge and
ability to select, install, service and bypass all the
components of an electrical or mechanical lock
-M-
MACS abb. maximum adjacent cut specification
manipulation key n. any key other than a correct
key which can be variably positioned and/or
manipulated in a keyway to operate a lock or cylinder
master disc n. a special disc tumbler with multiple
gates to receive a sidebar, see also “master pin”
definition 1, see also “stepped tumbler”.
master key n. a key which operates all the master
keyed locks or cylinders in a group, each lock or
cylinder usually operated by its own change key
v. to combinate a group of locks or cylinders such
that each is operated by its own change key as well
as by a master key for the entire group
master key changes n. the number of different
usable change keys available under a given master key
master key system n. 1. any keying arrangement
which has two or more levels of keying 2. a keying
arrangement which has exactly two levels of keying
master keyed adj. of or pertaining to a cylinder or
group of cylinders which are or are to be combinated
so that all may be operated by their own change
key(s) and by additional key(s) known as master
key(s)
master keyed only adj. of or pertaining to a lock
or cylinder which is or is to be combinated only to
a master key
master lever n. a lever tumbler which can align some
or all other levers in its lock so that their gates are at
the fence. It is typically used in locker locks.
master pin n. 1. usually a cylindrical shaped
tumbler, flat on both ends, placed between the top
and bottom pin to create an additional shear line
2. a pin tumbler with multiple gates to accept
a sidebar
master wafer n. a ward used in certain binary type
disc tumbler key-in-knob locks, see also “master pin”
definition 1, see also “stepped tumbler”
matrix format master keying n. a method of
generating combinations and assigning key symbols
in a master key system through the use of a matrix
maximum adjacent cut specification n. the
maximum allowable difference between adjacent
cut depths
meter lock n. 1. a padlock whose shackle consists
of a single removable post, designed for locking
utility meters or valves. 2. any of several small
devices specifically designed to lock utility meters
or valves and which require either a key or special
wrench for removal.
mis-cut adj. of or pertaining to a key which has
been cut incorrectly n. a mis-cut key
MK abb. master key
MK'd abb. master keyed
MK'd only abb. master keyed only
mogul cylinder n. a very large pin tumbler cylinder
whose pins, springs, key, etc. are also proportionally
increased in size. It is frequently used in prison locks.
mortise cylinder n. a threaded cylinder typically
used in mortise locks of American manufacture
multi-section key blank n. a key section which
enters more than one, but not all keyways in
a multiplex key system
multiple gating n. a means of master keying by
providing a tumbler with more than one gate
multiplex key blank n. any key blank which is part
of a multiplex key system
multiplex key system n. 1. a series of different key
sections which may be used to expand a master key
system by repeating bittings on additional key
sections. The keys of one key section will not enter
the keyway of another key section. This type of
system always includes another key section which
will enter more than one, or all of the keyways.
2. a keying system which uses such keyways and
key sections
mushroom pin n. a pin tumbler, usually a top pin,
which resembles a mushroom. It is typically used to
increase pick resistance
35
-N-
NCK sym. symbol for "no change key," primarily
used in hardware schedules
neck (of a key) n. 1. the portion of a bit key
between the shoulder and the bit(s) 2. the portion
of a cylinder key between the shoulder and the bow
negative locking n. locking achieved solely by
spring pressure or gravity which prevents a key cut
too deeply from operating a lock or cylinder
NKR abb. non key retaining
NMK sym. symbol which means "not master keyed"
and is suffixed in parentheses to the regular key
symbol. It indicates that the cylinder is not to be
operated by the master key(s) specified in the regular
key symbol; e.g., AB6(NMK).
non-fail safe adj. a feature of a security device
designed to remain engaged, for security purposes,
during a power loss
non key retaining adj. of or pertaining to a lock
whose key can be removed in both the looked and
unlocked positions
non-original key blank n. any key blank other than
an original
non removable key adj. a key which has one
or more cuts on it which trap the key in the lock
upon insertion
nose n. the part of a non-cylinder lock which
contains the keyway and rotates within a horn
NRK abb. non removable key
NRP abb. non removable pin
-Oodometer
method n. a means of progressing key
bittings using a progression sequence of right to left.
one bitted adj. of or pertaining to a cylinder which
is or is to be combinated to keys cut to the
manufacturer's reference number one bitting
one column progression n. a process wherein key
bittings are obtained by using the cut possibilities
in one column of the key bitting array
one pin master key n. a master key for all
combinations obtained by progressing only one
bitting position
open gated adj. pertaining to a lever tumbler whose
gate is in the edge of the tumbler
opening index n. the index or mark to which a
combination is dialed in order to effect an opening
operating key n. any key which will properly
operate a lock or cylinder to lock or unlock the lock
mechanism and is not a control key or reset key,
see also “change key”

Terminology
operating shear line n. any shear line which allows
normal operation of a cylinder or lock
original key blank n. a key blank supplied by
the lock manufacturer to fit that manufacturer's
specific product
-Ppack
n. the set of tumblers in a lever tumbler or
combination lock
padlock n. a detachable and portable lock with a
shackle which locks into its case
page master key n. the three-pin master key for
all combinations listed on a page in the standard
progression format
paracentric adj. 1. of or pertaining to a keyway with
one or more wards on each side projecting beyond the
vertical center line of the keyway to hinder picking
2. of or pertaining to a key blank made to enter such
a keyway
pattern key n. 1. an original key kept on file to
use in a key-duplicating machine when additional
keys are required 2. any key which is used in a keyduplicating
machine to create a duplicate key
personal identification number n. a series of
numbers and/or letters associated with a particular
individual as a means of identification
pick n. a tool or instrument, other than the
specifically designed key, made for the purpose of
manipulating tumblers in a lock or cylinder into the
locked or unlocked position through the keyway,
without obvious damage. v. to manipulate tumblers
in a keyed lock mechanism through the keyway,
without obvious damage, by means other than the
specifically designed key
pick key n. a type of manipulation key, cut or
modified to operate a lock or cylinder
pin v. to install pin tumblers into a cylinder and/
or cylinder plug, see also “pin tumbler”
PIN abb. personal identification number
pin chamber n. the corresponding hole drilled into
the cylinder shell and/or plug to accept the pin(s)
and spring
pin kit n. a type of keying kit for a pin tumbler
mechanism
pin stack n. all the tumblers in a given pin chamber,
see also “pin stack height”
pin stack height n. the measurement of a pin stack,
often expressed in units of the lock manufacturer’s
increment or as an actual dimension
pin tray n. see “layout tray”
pin tumbler n. usually a cylindrical shaped
tumbler. Three types are normally used: bottom pin,
master pin and top pin.
pin tweezers n. pl. a tool used in handling tumblers
and springs
pinning block n. a holding fixture which assists
in the loading of tumblers into a cylinder or
cylinder plug
pinning chart n. a numerical diagram which
indicates the sizes and order of installation of the
various pins into a cylinder. The sizes are usually
indicated by a manufacturer's reference number
which equals the quantity of increments a
tumbler represents.
plug n. the part of a cylinder which contains the
keyway, with tumbler chambers usually corresponding
to those in the cylinder shell
plug follower n. a tool used to allow removal of
the cylinder plug while retaining the top pins, springs,
and/or other components within the shell
plug holder n. a holding fixture which assists in the
loading of tumblers into a cylinder plug
plug retainer n. the cylinder component which
secures the plug in the shell
positive locking n. the condition brought about
when a key cut which is too high forces its tumbler
into the locking position. This type of locking does
not rely on gravity or spring pressure.
post (of a key) n. the portion of a bit key between
the tip and the shoulder, to which the bit(s)
is attached
practical key changes n. pl. the total number of
usable different combinations available for a specific
cylinder or lock mechanism
privacy key n. a key which operates an SKD
cylinder, see also “emergency key”
profile cylinder n. a cylinder with a usually uniform
cross section, which slides into place and usually
is held by a mounting screw. It is typically used in
mortise locks of non-U.S. manufacture.
progress v. to select possible key bittings, usually in
numerical order, from the key bitting array
progression n. a logical sequence of selecting
possible key bittings, usually in numerical order from
the key bitting array
progression column n. a listing of the key bitting
possibilities available in one bitting position as
displayed in a column of the key bitting array
progression list n. a bitting list of change keys and
master keys arranged in sequence of progression
progressive n. any bitting position which is
progressed rather than held constant
proprietary adj. of or pertaining to a keyway and
key section assigned exclusively to one end user by the
lock manufacturer. It may also be protected by law
from duplication.
36
pull bump key n. a lock picking key that must be
pulled from the lock one space position between
impacts
push bump key n. a lock picking key that centers
itself after each impact
-Rradiused
blade bottom n. the bottom of a key blade
which has been radiused to conform to the curvature
of the cylinder plug it is designed to enter
random master keying n. any undesirable process
used to master key which uses unrelated keys to create
a system
rap v. 1. to unlock a plug from its shell by striking
sharp blows to the spring side of the cylinder while
applying tension to the plug 2. to unlock a padlock
shackle from its case by striking sharp blows to the
sides in order to disengage the locking dogs
ratchet lock n. any lock which incorporates a ratchet
device allowing locking in more than one position
read v. to decode a lock combination visually
without disassembly of the lock or cylinder
recombinate v. to change the combination of a lock,
cylinder or key
recore v. to rekey by installing a different core
register groove n. the reference point on the key
blade from which some manufacturers index the
bitting depths
rekey v. to change the existing combination of
a cylinder or lock
removable cylinder n. a cylinder which can be
removed from a locking device by a key and/or tool
removable shackle adj. referring to a type of padlock
which is unlocked by removing the shackle from
the case
repin v. to replace pin tumblers, with or without
changing the existing combination
restricted adj. of or pertaining to a keyway and
corresponding key blank whose sale and/or
distribution is limited by the lock manufacturer in
order to reduce unauthorized key proliferation
retainer n. a component which is clipped or staked
in place to maintain the working relationship of
other components
RH abb. right hand
RHR abb. right hand reverse bevel
rim cylinder n. a cylinder typically used with surface
applied locks and attached with a back plate and
machine screws. It has a tailpiece to actuate the
lock mechanism.

Terminology
rim lock n. a lock or latch typically mounted on the
surface of a door or drawer
RL abb. The title “Registered Locksmith” as awarded
by ALOA
RM abb. row master key
root depth n. the dimension from the bottom of
a cut on a key to the bottom of the blade
rotating constant n. one or more cut(s) in a key of
any level which remain constant throughout all levels
and are identical to the top master key cuts in their
corresponding positrons. The positions where the top
master key cuts are held constant may be moved,
always in a logical sequence.
rotating constant method n. a method used to
progress key bittings in a master key system,
wherein at least one cut in each key is identical to the
corresponding cut in the top master key. The identical
cut(s) is moved to different locations in a logical
sequence until each possible planned position has
been used.
row master key n. the one-pin master key for all
combinations listed on the same line across a page
in the standard progression format
-S-
S/A abb. sub-assembled
Scandinavian padlock n. a cast case padlock with an
elliptical cross section. The locking mechanism is a
set of rotating disc tumblers, which engage notches in
the cast shackle and may be rotated by the angled cuts
cast on the key.
screen door lock n. a lock designed for the thin
stiles typically found on screen and storm doors
second generation duplicate n. a key reproduced
from a first generation duplicate
security collar n. a protective cylinder collar, see also
“cylinder guard”
selective key system n. a key system in which every
key has the capability of being a master key. It is
normally used for applications requiring a limited
number of keys and extensive cross keying.
selective master key n. an unassociated master key
which can be made to operate any specific lock(s)
in the entire system in addition to the regular master
key(s) and/or change key(s) for the cylinder without
creating key interchange
sequence of progression n. the order in which
bitting positions are progressed to obtain change key
combinations
seven column progression n. a process wherein key
bittings are obtained by using the cut possibilities
in seven columns of the key bitting array
seven pin master key n. a master key for all
combinations obtained by progressing seven
bitting positions
shackle n. 1. the part of a padlock, which passes
through an opening in an object or fits around an
object and is ultimately locked into the case
2. the portion of a restraint which fits around the
wrist, ankle, neck, waist or thumb
shackle retaining pin n. a pin which keeps an
unlocked shackle heel in the case
shackle spring n. a spring which pushes the shackle
into the open position when the padlock is unlocked
shear line n. a location in a cylinder at which
specific tumbler surfaces must be aligned, removing
obstruction(s) which prevented the plug from moving
shell n. the part of the cylinder which surrounds the
plug and which usually contains tumbler chambers
corresponding to those in the plug
shim n. a thin piece of material used to unlock the
cylinder plug from the shell by separating the pin
tumblers at the shear line, one at a time v. to unlock
a cylinder plug from its shell by using a shim
shoulder n. any key stop other than a tip stop,
see also “bow stop”
shove knife n. a tool used with a set-up plug
which pushes the springs and pin tumblers into the
cylinder shell
shrouded shackle n. a shackle which is protected
from cutting or tampering by design or by the use
of secondary shields
sidebar n. a cylinder component which enters gate(s)
in tumbler(s) to allow plug rotation
sidebar lock n. a lock mechanism which
incorporates a sidebar
simplex key section n. a single independent
key section which cannot be used in a multiplex
key system
single-acting lever tumbler n. a lever tumbler which
must be moved a minimum distance to allow travel of
a bolt, but cannot be moved so far as to restrict travel
of the bolt
single key section n. an individual key section
which can be used in a multiplex key system
single step progression n. a progression using
a one increment difference between bittings of
a given position
six column progression n. a process wherein key
bittings are obtained by using the cut possibilities
in six columns of the key bitting array
six pin master key n. a master key for all
combinations obtained by progressing six
bitting positions
37
SKD sym. symbol for "single keyed", normally
followed by a numerical designation in the standard
key coding system; e.g., SKD1, SKD2, etc.
It indicates that a cylinder or lock is not master keyed
but is part of the keying system
SMK abb. sub-master key
spacing n. the dimensions from the stop to the
center of the first cut and/or to the centers of
successive cuts
spindle n. a component which transfers rotary
motion from outside a lock or latch case to an
inner mechanism
split pin master keying n. a method of master
keying a pin tumbler cylinder by installing master
pins into one or more pin chambers
spool pin n. usually a top pin which resembles
a spool, typically used to increase pick resistance
spring cover n. a device for sealing one or more
pin chambers
spring seat n. the point at which a spring
is anchored, located or attached and at which
(from which) it exerts force
standard key coding system n. an industry standard
and uniform method of designating all keys and/
or cylinders in a master key system. The designation
automatically indicates the exact function and keying
level of each key and/or cylinder in the system,
usually without further explanation.
standard progression format n. a systematic
method of listing and relating all change key
combinations to all master key combinations in
a master key system. The listing is divided into
segments known as blocks, horizontal groups, vertical
groups, rows, and pages, for levels of control.
stepped tumbler n. a special (usually disc) tumbler
used in master keying. It has multiple bearing surfaces
for blades of different key sections.
stop (of a key) n. the part of a key from which all
cuts are indexed and which determines how far the
key enters the keyway
sub-master key n. the master key level immediately
below the master key in a system of six or more levels
of keying
substitution code n. a code whose individual
characters are converted to individual key cuts or
combination numbers by means of a reference table
-T-
T-handle n. a T-shaped handle assembly which may
be lockable
tailpiece n. an actuator attached to the rear of the
cylinder, parallel to the plug, typically used on rim,
key-in-knob or special application cylinders

Terminology
theoretical key changes n. pl. the total possible
number of different combinations available for
a specific cylinder or lock mechanism
three column progression n. a process wherein key
bittings are obtained by using the cut possibilities
in three columns of the key bitting array
three pin master key n. a master key for all
combinations obtained by progressing three
bitting positions
three point latch n. a self-latching device designed
to latch a door at the top, bottom and edge
throw member n. an intermediate actuator which
engages the rear of the plug to transfer motion to
a cam, tailpiece or other actuator
tip n. the portion of the key which enters the
keyway first
tip stop n. a type of stop located at or near the tip
of the key
TMK abb. top master key
toe (of a shackle) n. that part of the shackle,
which may be removed from the padlock body
tolerance n. the deviation allowed from a given
dimension
top master key n. the highest level master key in
a master key system
top of blade n. the bitted edge of a single bitted key
top pin n. usually a cylindrical shaped tumbler,
usually flat on both ends and installed directly under
the spring in the pin stack
total position progression n. a process used to
obtain key bittings in a master key system wherein
bittings of change keys differ from those of the top
master key in all bitting positions
try-out key n. a manipulation key which is usually
part of a set, used for a specific series, keyway,
and/or brand of lock
tubular key n. a key with a tubular blade. The key
cuts are made into the end of the blade, around its
circumference.
tubular key cylinder n. a cylinder whose tumblers
are arranged in a circle and which is operated by
a tubular key
tumbler n. a movable obstruction of varying size
and configuration in a lock or cylinder which makes
direct contact with the key or another tumbler
and prevents an incorrect key or torque device from
activating the lock or other mechanism
tumbler spring n. any spring which acts directly
on a tumbler
two column progression n. a process wherein key
bittings are obtained by using the cut possibilities
in two columns of the key bitting array
two pin master key n. a master key for all
combinations obtained by progressing two bitting
positions
two-step progression n. a progression using
a two increment difference between bittings of
a given position
-U-
UL abb. Underwriters Laboratories
UL listed adj. listed in a directory as having passed
specific Underwriters Laboratories testing
unassociated change key n. a change key which is
not related directly to a particular master key through
the use of certain constant cuts
unassociated master key n. a master key which
does not have change keys related to its combination
through the use of constant cuts
uncombinated adj. 1. of or pertaining to a cylinder
which is or is to be supplied without keys,
tumblers and springs 2. of or pertaining to a lock,
cylinder or key in which the combination has not
been set
38
uncontrolled cross keying n. a condition in which
two or more different keys under different higher
level keys operate one cylinder by design; e.g.,
XAA1 operated by AB, AB1. Note: This condition
severely limits the security of the cylinder and the
maximum expansion of the system, and often leads
to key interchange.
unidirectional cylinder n. a cylinder whose key can
turn in only one direction from the key pull position
-Vvertical
group master key n. the two-pin master
key for all combinations listed in all blocks in a line
down a page in the standard progression format
VGM abb. vertical group master key
visual key control n. a specification that all keys
and the visible portion of the front of all lock
cylinders be stamped with standard keying symbols
VKC abb. visual key control
virtual key section n. a secondary locking
mechanism combination used as a method of
discriminating between suppliers for key control
-Wward
n. a usually stationary obstruction in a lock
or cylinder which prevents the entry and/or operation
of an incorrect key
ward cut n. a modification of a key which allows
it to bypass a ward
warded adj. having one or more wards
-X-
X sym. symbol used in hardware schedules to
indicate a cross-keyed condition for a particular
cylinder; e.g., XAA2, XlX (but not AX7)
-Zzero
bitted adj. of or pertaining to a cylinder
which is or is to be combinated to keys cut to the
manufacturer's reference number "0" bitting

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